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QP40.H211898       Essentials  of  physio 


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Essentials  of 
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AND   SURGEONS 


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Reference  Library 

Given 


Essentials  of  Ph; 

Revised  and 

(Price,  81.00  n 
Essentials  of  Sun 

on  Antiseptic 

ward  Marti: 
Essentials  of  Ana 

180  illustrate 

M.D. 
Essentials  of  Me< 

organic.    By 
Essentials  of  Obs 

larged.   75  illi 

ton,  M.  D. 
Essentials  of  Pathology  and  Morbid  Anatomy.    6th 

thousand.    46  illustrations.    By  C.  E.  Armand 

Semple,  M.  D. 
Essentials  of  Materia  Medica.     Therapeutics  and 

Prescription-Writing.    4th  edition.    By  Henry 

Morris,  M.  D. 
Essentials  of  Practice  of  Medicine.     By  Henry 

Morrb,  M.  D.    An  Appendix  on  Urine  Exami- 
nation.    Illustrated.     By  Lawrence   Wolff, 

M.  D.  3d  edition,  enlarged  by  some  300  Essential 

Formulae,  selected  from  eminent  authorities,  by 

Wm.  M.  Powell,  M.  D.    (Double  number,  price, 

82.00.) 
Essentials  of  Diseases  of  the  Skin.    3d  edition.    71 

letter-press  cuts  and  15  half-tone  illustrations. 

By  Henry  W.  Stelwagon,  M.  D.    ($1.00  net.) 


by 


-^.V 


/ERS. 

md  answers, 
,  often  is  at  a 
ually  puzzled 
estions  could 


ND  SERIES. 

LEASON,     S.  B.,     M.  D, 

ispensary  of  Philadel- 

iccurately  repre- 
11  in  compass,  it 
upward  of  200 
original  sources. 

IES. 

th  edition.  With  6211- 
;.  Cragin.M.D. 
Bandaging, and  Vene- 
rations.    By  Edward 

s  Toxicology,  and  Hy- 
By  C.  E.  Armand  Sem- 

Eye,  Nose?  and  Throat. 
'ised  edition.  By  Ed- 
1  E.  B.  Gleason,  M.  D. 
ildren.  4th  thousand. 
,M.D. 

_^ f  Urine.   Colored  "Vo- 

~  "gel  Scale,"  with  numerous  illustrations.    By 

Lawrence  Wolff,  M.  D.    (Price,  75  cents.) 
Essentials  of  Diagnosis.    By  S.  Solis-Cohen,  M.  B., 
and  A.  A.  Eshner,  M.D.    Illustrated.    (Price, 
$1.50  net.) 
Essentials  of  Practice  of  Pharmacy.  By  L.  E.  Sayrb. 

2d  edition,  revised. 
Essentials  of  Bacteriology.    81  illustrations  and  five 
plates.  2d  edition,  revised.    By  M.  V.  Ball,  M.  D. 
Essentials  of  Nerrous  Diseases' and  Insanity.    48 

illustrations.    By  John  C.  Shaw,  M.  D. 
Essentials  of  Medical  Physics.  155  illustrations.  By 

Fred  J.  Brockway,  M.  D.    (Price,  81.00  net.) 
Essentials  of  Medical  Electricity.    65  illustrations. 
By  David  D.  Stewart,  M.  D.,  and  Edwakd  S. 
Lawrance,  M.  D. 


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ESSENTIALS 


PHYSIOLOGY. 


Since  the  issue  of  the  first  volume  of  the 
Saunders  Question=Compends, 

OVER  160,000  COPIES 

of  these  unrivalled  publications  have  been  sold. 
This  enormous  sale  is  indisputable  evidence 
of  the  value  of  these  self-helps  to  students 
and  physicians. 


SAUNDERS'  QUESTION-COMPENDS,  NO.  1. 

ESSENTIALS  OF  PHYSIOLOGY 

ARRANGED    IN    THE   FORM  OF 

QUESTIONS  AND  ANSWERS, 

PREPARED    ESPECIALLY   FOR 

STUDENTS  OF  MEDICINE. 

BY 

HOBART  AMORY   BARE,  M.D., 

PROFESSOR  OF  THERAFEI    i  I<  -    ami    MATERIA    MEDICA    IN   THE  JEFFERSON 
MEDICAL    COLLEGE    OF    I'll  1 1. A  ln:i  nil  A  ;     PHYSICIAN    To    Till;    JEF- 
FERSON  MEDICAL  COLLEGE   HOSPITAL;    MEMBER  OF  THE 
ASSOCIATION  of  AMERICAN    PHYSICIANS. 


FOURTH  EDITION,  THOROUGHLY  REVISED  AND  ENLARGED. 

i  ONI  AININQ 

A  SERIES  OF   HANDSOME   PLATE    [LLUSTBATIONS  TAKEN    FROM    I  in: 
CELEBRATED   "ICONSS  NERVORUM  CAPITIS"   OF  ARNOLD. 


PHILADELPHIA: 
\V.    I',.    SAUND  E  lis, 

925    W  \  i.Ni   r    Si  REET. 

1898. 


Copyright,  1897, 

BY 

W.    F. .   SAUNDERS 

Press  of 
W.  B.  Saunders,  Philadelphia. 


PREFACE  TO  FOURTH  EDITION. 


At  the  request  of  the  publisher,  and  with  the  con- 
sent of  Dr.  Hare,  the  work  of  revising  this  book  for 
the  fourth  edition  has  been  undertaken  by  Dr.  J.  H. 
Raymond.  The  original  text  has  almost  wholly  been 
retained,  alterations  being  made  only  where  necessary  to 
bring  the  subject  under  consideration  abreast  with  the 
teachings    of  the   day. 

(v) 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 
Columbia  University  Libraries 


http://www.archive.org/details/essentialsofphysOOhare 


PKKFACE  TO  FIRST  EDITION. 


At  the  present  time,  when  the  student  is  forced  by  the 
rapid  progress  of  medical  science  to  imbibe  an  amount  of 
knowledge  which  is  far  too  great  to  permit  of  an  attempt 
on  his  part  to  master  it,  any  book  which  contains  the 
"essentials"  of  a  science  in  a  concise  yet  readable  form 
must  of  necessity  be  of  value.  The  trite  saying  that  "there 
is  no  short  road  to  knowledge  "  is,  of  course,  as  true  as  it 
is  old,  and  for  this  reason  many  of  the  medical  profession 
have  looked  with  disfavor  on  books  of  this  character,  as 
being  the  means  by  which  students  might  attempt  the 
shorter  path. 

No  one  desires  more  than  the  writer  that  the  depth  and 
scope  of  medical  education  may  be  increased,  but  in  his 
belief  the  evil  at  present  in  existence  consists  in  the  fact 
that  medical  institutions,  by  granting  a  degree  too  early, 
make  the  short  road  to  knowledge  the  only  one  which  the 
student  with  the  average  amount  of  cerebral  gray  matter 
can  possibly  travel.  The  evil  lies  with  the  small  amount 
of  time  required  for  the  obtaining  of  the  degree,  not  with 
those  books  which  are  called  into  existence  by  the  short- 
ness of  the  medical  curriculum. 

(  vii  ) 


viii  PREFACE. 

The  usefulness  of  arranging  the  subject  in  the  form  of 
questions  and  answers  will,  the  writer  thinks,  be  apparent, 
since  the  student,  in  reading  the  standard  works  on  Phys- 
iology, often  is  at  a  loss  to  discover  the  important  points 
to  be  remembered,  and  is  equally  puzzled  when  he  attempts 
to  formulate  ideas  as  to  the  manner  in  which  the  question 
could  be  put  in  the  examination-room. 

A  manual  of  this  character  is  in  no  one  way  intended  to 
supplant  any  of  the  text-books,  but  to  contain,  as  its  title 
declares,  the  essence  of  those  physiological  facts  with  which 
the  average  student  must  be  familiar. 

After  considerable  thought,  it  has  been  considered 
advisable  to  exclude  points  which  may  be  called  purely 
anatomical,  and  which  deprive  some  of  the  smaller  books 
on  Physiology  of  the  space  which  might  otherwise  be 
occupied  by  purely  physiological  statements.  The  results 
reached  every  day  by  physiological  experimenters  are 
many  of  them  so  contradictory  that  no  attempt  to  give 
individual  opinions  or  teachings  has  been  attempted,  the 
statements  made  being  supposed  to  represent  those  facts 
most  generally  accepted  and  taught.  The  student  will, 
therefore,  find  statements  which  are  not  in  accord  with 
those  taught  by  his  instructor,  and  it  is  for  this  purpose 
that  the  interleaved  edition  has  been  published,  in  order 
that  individual  teachings  may  be  noted  and  remembered. 
In  the  compilation  of  the  facts  here  rehearsed,  the  standard 
works  of  Landois,  Yeo,  Foster,  Dalton,  Baker,  Hermann, 
and  Chapman  have  all  been  consulted. 


CONTENTS. 


PAGE 

Proteids 18 

Carbo-hydrates 20 

The  blood 21 

Coagulation  of  blood 28 

The  heart 31 

Respiration 48 

The  nervous  mechanism  of  respiration    ....  53 

Digestion         ..........  54 

The  stomach GO 

Pancreatic  digestion 66 

The  liver 68 

Absorption .73 

Animal  heat 76 

The  kidneys 81 

The  urine 90 

The  skin 95 

Secretion 97 

The  mammary  glands 98 

The  bodily  metabolism 98 

General  view  of  the  most  important  substances  used  as  food  99 

Milk 99 

The  muscles 104 

The  nervous  system 112 

The  physiology  of  the  spinal  nerves 117 

The  physiology  of  the  cerebro-spiual  nervous  system     .         .118 

The  functions  of  the  spinal  cord 122 

The  medulla  oblongata 128 

The  cranial  nerves  .                 141 

(IX) 


CONTENTS. 


The  special  senses   . 

The  sensibility  of  the  skin 

The  sense  of  taste    . 

The  sense  of  smell    . 

The  sense  of  sight    . 

Hearing    .... 

The  voice  and  speech 

The  sympathetic  nerve     . 
Generation  and  development  . 

Generative  organs  of  the  female 

The  male  sexual  organs   . 

Development    . 
The  development  of  organs     . 

Vertebral  column  and  cranium 

Extremities 

Heart  and  bloodvessels     . 

Nervous  system 

Eye 

Ear 

Nose.        .... 

Alimentary  canal  and  organs 

The  foetal  circulation 


PAGE 

145 

146 
147 
148 
149 
158 
161 
165 
167 
168 
171 
178 
179 
179 
180 
180 
181 
182 
183 
183 
183 
184 


PLATE    I. 


DESCRIPTION  OF  THE  PLATES. 


PLATE    I. 

POSITION  AND  COURSE  OF  THE  CRANIAL  NERVES  WITHIN 
THE  SKULL. 

This  plate  shows  the  course  of  the  cranial  nerves  within  the  skull 
and  through  the  foramina  of  the  dura  mater,  and  the  plexuses  of 
nerves  accompanying  the  arteries  at  the  hase  of  the  brain. 

The  skull  being  removed  by  a  horizontal  section  from  the  glabella 
to  the  external  occipital  protuberance,  the  brain  and  tentorium  cere- 
belli  are  taken  out,  leaving  in  view  the  arteries  and  roots  of  the  nerves 
at  the  base  of  the  brain. 

A. — Superior  part  of  the  helix  of  the  right  and  left  ears. 

15. — Skin  and  adipose  tissue. 

C. — Frontal  portion  of  occipito -frontalis  muscle. 

1). — Temporal  muscle. 

E. — Occipital  portion  of  the  occipito-frontalis  muscle,  a.  Frontal 
artery.  6.  Supraorbital  artery,  c.  Anterior,  and  d,  posterior 
temporal  arteries,     e.  Occipital  artery. 

F. — Frontal  bone.  /.  Frontal  crest,  g.  Groove  for  the  superior  lon- 
gitudinal sinus. 

G. — Parietal  bone  ;  h,  its  anterior,  and  i,  posterior  inferior  angles. 

H. — Squamous  portion  of  the  temporal  hone. 

I. — Tabular  portion  of  the  occipital  bone.  k.  Internal  occipital  pro- 
tuberance. 

K. — Crista  galli. 

L. — The  dura  mater  covering  the  anterior  cranial  fossa,  cerebral 
ridges,  and  digital  impressions,  /,  and  the  cribriform  plate  of 
the  ethmoid  bone,  m.  n.  Anterior  portion  of  the  f'al\  cerebri 
with  the  superior  longitudinal  sinus,  ■•. 

(xi) 


Xll  DESCRIPTION    OF    THE    PLATES. 

31. — Middle  cranial  fossa,  covered  by  dura  inater.  p.  Posterior  cli- 
noid  processes,  q.  Dorsum  ephippii.  r.  Anterior  clinoid 
processes,  s.  Pituitary  body  and  infundibulum.  t.  Dia- 
phragm of  the  sella  Turcica,     u.  Superior  petrosal  sinus. 

N. — Posterior  cranial  fossa,  v.  Falx  cerebelli.  w.  Torcular  Hero- 
phili.  x.  Lateral  sinuses,  y.  Mastoid  emissary  vein.  z. 
Opening  of  the  lateral  sinus  into  the  bulb  of  the  internal 
jugular  vein. 

O. — Foramen  magnum. 

P. — Lower  portion  of  the  medulla  oblongata,  a.  Anterior  median 
fissure.  @.  Posterior  median  fissure,  y.  Central  gray  mat- 
ter with  central  canal  of  the  spinal  cord.  J.  Anterior,  and  e, 
posterior  gray  horns.  £.  Pyramids.  ».  Lateral  columns. 
Sh  Posterior  columns. 

Q. — Vertebral  arteries,  i.  Anterior  spinal  artery,  x.  Posterior  in- 
ferior cerebellar  artery,  x.  Posterior  spinal  artery,  /x.  Basi- 
lar artery,  v.  Branches  to  the  pons.  £.  Anterior  inferior 
cerebellar  artery,  o.  Internal  auditory  artery,  it.  Superior 
cerebellar  artery,     p.  Posterior  cerebral  artery. 

K. — Internal  carotids.  <r.  Posterior  communicating  artery,  r.  An- 
terior choroid  artery,  v.  Middle  cerebral  artery.  <f>.  Ante- 
rior cerebral  artery.     %.  Anterior  communicating  artery. 

I. — Olfactory  nerve. 

II. — Optic  nerve. 

III. — Motor  oculi  nerve. 

IV. — Pathetic  nerve. 

V. — Trifacial  nerve. 

VI. — Abducens  nerve. 

VII. — Facial  nerve.     1.   Its  greater,  and  2,  lesser  portions. 

VIII. — Auditory  nerve. 

IX. — Glosso-pharyngeal  nerve. 

X. — Pneumogastric  nerve. 

XL — Spinal  accessory  nerve.     3.  Its  cranial,  and  4,  spinal  roots. 

XII. — Hypoglossal  nerve. 

The  carotid  and  vertebral  arteries  are  accompanied  by  sympathetic 

plexuses,  derived  from  the  superior  and  inferior  cervical,  and  some- 
times from  the  superior  thoracic  ganglia. 


PLATE    II 


DESCRIPTION    OF    THE    PLATES, 


PLATE    II. 

COURSE  OF  THE  CRANIAL  NERVES  THROUGH  THE  FORAMINA 
OF  THE  SKULL,  AND  IN  THE  ORBIT  AND  TEMPORAL  FOSSA. 

On  tin'  right  side  the  semilunar  ganglion,  recurrent  branches  of  the 
first,  second,  and  third  divisions  of  the  trifacial  nerve,  and  the  upper- 
most nerves  of  the  orbit  are  in  view. 

To  the  left  are  seen  the  conrse  of  the  cranial  nerves  through  the 
foramina  of  the  skull,  t lie  deeper  nerves  of  the  orbit,  and  the  nerves 
of  the  temporal  fossa. 

The  calvarium  being  removed,  the  brain,  together  with  the  carotid 
and  vertebral  arteries,  is  taken  out. 

To  the  right  the  dura  mater  and  tentorium  cerehelli  are  in  their 
natural  position,  the  lateral  and  superior  petrosal  sinuses  being 
opened,  but  the  meningeal  layer  of  the  dura  mater  of  the  middle 
cranial  fossa  is  removed,  as  is  also  the  roof  of  the  orbit,  so  that  not 
only  the  triangular  plexus,  semilunar  ganglion,  the  first,  second,  and 
third  divisions  of  the  trifacial,  with  their  recurrent  branches,  hut  also 
the  course  of  the  supraorbital,  lachrymal,  and  pathetic  nerves  may  be 
seen. 

To  the  left,  the  dura  mater  which  covers  the  base  of  the  skull  is  re- 
moved. The  orbit,  temporal  fossa,  tympanic  cavity,  internal  auditory 
meatus,  and  facial  canal  are  exposed  to  view.  The  supraorbital, 
lachrymal,  and  pathetic  nerves  are  cut  away,  and  the  levator  palpebral 
superioris  ami  superior  rectus  muscles  are  divided  and  turned  aside. 

To  the  left,  therefore,  are  seen  the  course  of  the  cranial  nerves 
through  the  foramina  of  the  skull  ;  the  position  and  course  of  the 
optic,  nasal,  superior  branches  of  the  motor  oculi  and  the  abducens 
nerves  ;  the  origin  and  course  of  the  buccal,  deep  temporal,  masse- 
teric and  anterior  auricular  nerves  ;  and  finally  the  connections  of  the 
facial  and  auditory  nerves  ;  the  course  of  the  chorda  tympani  through 
the  tympanic  cavity,  and  the  position  of  the  greater  and  lesser 
superficial  petrosal  nerves  on  the  upper  surface  of  the  petrous  por- 
tion of  the  temporal  bone. 

A. — P.,  and  a — g,  indicate  the  same  structures  as  in  the  preceding 

plate. 
G. — Inferior  margin  of  the  parietal  bone. 


XIV  DESCRIPTION    OF    THE    PLATES. 

H. — Squamous  portion  of  the  right  temporal  bone.  h.  Left  cerebellar 
fossa,  i.  Foramen  magnum,  k.  Left  innominate  process. 
/.  Left  jugular  process,  m.  Jugular  notch,  n.  Left  poste- 
rior, and  o,  anterior  condyloid  foramina. 

K. — Petrous  portion  of  the  left  temporal  bone.  /;.  Sigmoid  fossa. 
q.  Mastoid  foramen.  r.  Mastoid  cells,  s.  Semicircular 
canals  partly  visible  and  partly  cut  away.  t.  Internal  audi- 
tory meatus,  u.  Tympanic  cavity,  v.  Head  of  the  malleus. 
w.  Incus,  x.  Posterior  lacerated  foramen,  y.  Apex  of  the 
petrous  portion  of  the  temporal  bone.  z.  Petro-sphenoidal 
ligament. 

Li, — Sphenoid  bone.  a.  Clivus  Blumenbachii.  8.  Posterior  clinoid 
processes,  y.  Olivary  process.  J.  Left  great  wing  of  the 
sphenoid  bone  partly  cut  away.  e.  Foramen  spinosum.  £. 
Foramen  ovale.  ».  Foramen  rotundum.  S-.  Roots  of  the 
right  lesser  wing  of  the  sphenoid  bone.  t.  Anterior  lacerated 
foramen,  x.  Optic  foramen,  between  the  roots  of  the  lesser 
wing  of  the  sphenoid  bone. 

31. — Cribriform  plate  of  the  ethmoid  bone.  X.  Anterior  ethmoidal 
foramen. 

N. — Inner  surface  of  the  temporal  muscle. 

O. — Upper  border  of  the  external  pterygoid  muscle. 

P. — Condyle  of  the  inferior  maxilla. 

Q. — Dura  mater,  ft.  Anterior  portion  of  the  falx  cerebri  and  of  the 
superior  longitudinal  sinus,  v.  Opening  for  the  passage  of 
the  trunk  of  the  trifacial  nerve.  £.  Posterior  portion  of  the 
falx  cerebri,  o.  Right  lateral  sinus,  ir.  Superior  petrosal 
sinus,     p.  Dura  mater  covering  the  posterior  cranial  fossa. 

K. — Lower  portion  of  the  medulla  oblongata. 

S. — Vertebral  artery.  On  the  left  it  may  be  seen  beneath  the  con- 
dyloid portion  of  the  occipital  bone  ;  and  on  the  right  it  is 
seen  passing  through  the  dura  mater. 

T. — Internal  carotid.  <r.  The  second,  t,  third,  and  u,  fourth  flexures 
of  the  left  internal  carotid. 

U. — Middle  meningeal  artery.  On  the  left  side  it  is  divided  near  the 
foramen  spinosum.  <p.  The  anterior  branch,  and  ^,  poste- 
rior branch  of  the  middle  meningeal  artery,  which  last  sends 
a  small  petrosal  branch  into  the  anterior  part  of  the  petrous 
portion  of  the  temporal  bone. 

V. — Posterior  deep  temporal  artery,  branch  of  the  internal  maxillary. 


DESCRIPTION  OF  THE  PLATES.  XV 

W. — Ophthalmic  artery.  ^.  Lachrymal  artery.  M.  Muscular 
branches,  aa.  Ciliary  arteries.  66.  Supraorbital  artery, 
ce.  Ethmoidal  artery,     dd.  Ophthalmic  artery  continuing 

course  to  the  inner  canthus. 
X. — Pituitary  body  and  part  of  the  infundibulum. 

Y.— The  eyeball. 

Z. — External  rectus  muscle.  .1.1.  Internal  rectus  muscle.  BB. 
Superior  oblique  muscle.     CC.  Levator  palpebral  superioris 

musole.      DD.   Superior  rectus  muscle. 
I. — Olfactory  nerve.     1.  Olfactory  tract,  and  2,  bulb  of  the  left  side. 

3.  Filaments  of  the  right  olfactory  nerve,  en  sheathed  by  the 
dura  mater,  entering  the  nasal  cavity  through  the  cribriform 
plate  of  the  ethmoid  bone. 

II. — Optic  nerve.  4.  Its  sheath.  On  the  left  side  the  course  of  the 
optic  nerve  may  1m-  seen  as  tar  as  the  eyeball. 

III.— Motor  oculi  nerve.  ").  Superior  branch,  going  to  the  superior 
rectus  and  levator  palpebrae  superioris  muscles.  6.  Inferior 
branch. 

IV. — Right  pathetic  nerve.  7.  Communicating  branch  of  the  first 
division  of  the  tilth  to  the  pathetic  nerve,  which  runs  in  its 
.-heath,  from  whence  it  soon  passes  to  the  internal  branch  oi 
the  supratrochlear  nerve.  8.  Distribution  of  the  pathetic 
nerve  to  the  superior  oblique  muscle. 

V. — Trunk  and  triangular  plexus  of  the  trifacial  nerve.  9.  Semi- 
lunar (or  Sasserian)  ganglion  of  the  fifth  pair.  10.  Small 
accessory  ganglion,  sometimes  found  in  the  triangular  plexus 
near  the  semilunar  margin  of  the  semilunar  ganglion.  11. 
First  division  of  the  trifacial.  12.  Recurrent  branch, 
which  runs  around  the  pathetic  and  divides  into  two 
branches,  (13),  which  go  as  far  as  the  lateral  sinus.  14. 
Lachrymal  nerve.  15.  Supraorbital  nerve.  1(>.  Frontal 
nerve.  17.  Supratrochlear  nerve.  1  8.  Two  filaments  which 
go  to  the  supratrochlear  nerve,  lit.  Nasal  nerve.  20.  Sensory 
root  of  the  ophthalmic  ganglion.  21.  Long  ciliary  nerves. 
21*.  Short  ciliary  nerves,  coming  from  the  ophthalmic  gang- 
lion. 22.  Nasal  nerve.  23.  Infratrochlear  nerve.  24. 
Second  division  of  the  trifacial.  25.  Recurrent  branch  of 
the  second  division  of  the  fifth.  25*.  Its  junction  with  the 
recurrent  branch  of  the  third  division  of  the  fifth.  26.  Third 
division   of  the   trifacial.     On   the   left  side  it  may   be   seen 


XVI        DESCRIPTION  OF  THE  PLATES. 

passing  through  the  foramen  ovale.  27.  Recurrent  branch 
of  the  third  division  of  the  fifth  nerve,  which  runs  within 
the  cranium  along  the  posterior  margin  of  the  middle  menin- 
geal artery,  joins  the  recurrent  branch  of  the  second  division 
of  the  fifth  (25*),  and  gives  off  a  lesser  anterior  petrosal 
branch  (27*),  which  accompanies  the  anterior  petrosal  artery 
into  the  anterior  part  of  the  petrous  portion  of  the  temporal 
bone,  while  it  goes  to  the  posterior  part  of  the  petrous  por- 
tion of  the  temporal  bone  with  the  posterior  branch  of  the 
middle  meningeal  artery,  or  a  special  posterior  petrosal 
branch  of  this  artery.  The  origin  of  this  recurrent  nerve  is 
shown  in  the  first  figure  of  the  fourth  plate.  28.  Superior 
root  of  the  auriculo-temporal  nerve.  29.  Masseteric  nerve. 
30.  Posterior  deep  temporal  nerve.  31.  External  pterygoid 
nerve.    32.  Buccal  nerve.     33.  Anterior  deep  temporal  nerve. 

VI. — Abducens  nerve.  On  the  left  side  its  course  may  be  seen  on 
the  outer  side  of  the  internal  carotid  and  through  the  ante- 
rior lacerated  (34)  foramen.  35.  Distribution  of  the  abducens 
nerve  to  the  external  rectus  muscle  of  the  eye. 

VII. — Facial  nerve.  36.  Its  greater,  and  37,  lesser  portions.  38. 
The  internal,  and  39,  external  communications  of  the  facial 
with  the  auditory  nerve.  40.  Geniculate  ganglion.  41. 
Greater  superficial  petrosal  nerve.  42.  Chorda  tympaui 
nerve. 

VIII. — Auditory  nerve. 

IX. — Grlosso-pharyngeal  nerve.     43.  Lesser  superficial  petrosal  nerve. 

X. — Pneumogastric  nerve.  44.  Superior  vagal  ganglion,  or  ganglion 
of  the  Root. 

XI. — Spinal  accessory  nerve. 

XII. — Hypoglossal  nerve. 


PLATE    III. 


DESCRIPTION  OF  THE  PLATES.        xvn 


PLATE    III. 

THIS  WITH  PLATE  IV.  GIVES  AN  INNER  AND  POSTERIOR  VIEW 
OF  THE  CRANIAL  AND  CERVICAL  NERVES,  AND  THE 
CAROTID  AND  VERTEBRAL  ARTERIES,  BOTH  WITHIN  AND 
OUTSIDE  OF  THE  CRANIUM,  AND  OF  THE  SPINAL  CANAL. 

The  distribution  of  the  nerves  of  the  nasal  septum,  course  of  the 
posterior  crauial  and  superior  cervical  nerves,  and  the  position  of  the 
superior  cervical  ganglion  and  sympathetic  plexuses  on  the  arteries 
of  the  head  are  illustrated  in  this  diagram. 

The  right  side  of  the  head  and  half  of  the  cerebrum,  cerebellum, 
medulla  and  spinal  cord  are  removed  by  a  perpendicular  section  ;  the 
skull  and  the  bodies  of  the  cervical  vertebrae,  together  with  the  rectus 
capitis  anticus  major  and  minor  and  longus  colli  muscles.  The  basilar 
process  of  the  occipital  and  posterior  part  of  the  body  of  the  sphenoid 
bones  are  removed  ;  the  spinal  and  carotid  canals,  and  the  condyloid 
and  posterior  lacerated  foramina  are  opened,  the  osseous  and  carti- 
laginous nasal  septum  cut  away,  and  the  mucous  membrane  of  the 
pharynx  and  palate  and  the  genio-hyo-glossus  muscle  are  either  partly 
or  wholly  removed.  Therefore  the  following  structures  are  seen: 
firstly,  the  spinal  canal  covered  by  the  dura  mater,  and  the  vertebral 
vessels  and  roots  of  the  cervical  nerves  ;  secondly,  the  posterior  cranial 
fossa  and  the  recurrent  branch  of  the  vagHS  nerve,  the  hypoglossal, 
spinal  accessory,  vagus  and  glosso-pharyugeal  nerves,  both  within 
and  outside  of  the  cranium,  and  the  superior  cervical  ganglion  ; 
thirdly,  the  cavities  of  the  pharynx  and  larynx,  hard  and  soft  palate 
and  the  tongue  with  its  nerves  ;  finally,  the  common  carotid  lying 
between  the  pharynx  and  vertebra?,  the  internal  and  external  carotids 
and  the  sympathetic  plexuses  accompanying  the  carotid  and  vertebral 
arteries. 

A. — Gr. — Cervical  vertebra?  from  the  first  to  the  seventh,  n.  Arch  of 
the  vertebra?  sawed  through  the  centre,  h.  Left  apex  of  the 
spinous  processes,  c.  Posterior  root  of  the  transverse  pro- 
cesses. 

Jf. Occipital  bone.     d.  Left  condyle,     c.  Anterior  condyloid  foramen. 

f.  Tabular  portion  of  the  occipital  bone.     g.   External,   and 


XV111  DESCRIPTION    OF    THE    PLATES. 

h,  internal  occipital  protuberances,  i.  Foramen  magnum. 
k.   Posterior  cranial  fossa,  covered  by  dura  mater. 

I. — Interior  portion  of  parietal  bone. 

K. — Temporal  bone.  /.  Petrous  portion,  m.  Carotid  canal,  n.  In- 
ternal auditory  meatus,  o.  Squamous  portion  of  the  temporal 
bone  covered  by  dura  mater. 

Ii. — Sphenoid  bone.  p.  Its  body  partly  removed,  q.  Sphenoidal 
sinus,  r.  Lesser  wing.  s.  Greater  wing,  covered  by  dura 
mater,     t.  Middle  cranial  fossa,     u.  Optic  foramen. 

M. — Frontal  bone.  v.  Its  vertical  plate,  w.  Frontal  sinus,  x.  Or- 
bital plate,  covered  by  dura  mater,  y.  Digital  impressions 
and  cerebral  ridges,     z.  Anterior  cranial  fossa. 

N. — Cribriform  plate  of  the  ethmoid,  a.  Crista  galli  sawed  through 
the  centre. 

O. — Nasal  bone. 

P. — Palate  process  of  the  superior  maxillary.  6.  Anterior  palatine 
canal. 

Q. — Horizontal  plate  of  the  palate  bone.  y.  Posterior  palatine 
canal. 

R. — Inferior  maxillary,  sawed  through  the  centre.  5.  Genial 
tubercles. 

S. — Incisor  teeth. 

T. — Left  superior  canine  tooth. 

XJ. — Hyoid  bone.  s.  Body.  £.  Greater  cornu.  w.  Lateral  thyro- 
hyoid ligament. 

V. — Trapezius,  W,  splenius  capitis,  X,  biventer  cervicis,  Y,  semi- 
spinalis  colli,  and  Z,  interspinales  muscles.  A.  Rectus  capi- 
tis posticus  major,  and  B,  minor  muscles. 

r. — Orbicularis  oris  muscle. 

A. — Genio-hyo-glossus  muscle,  partly  removed  so  that  the  distribution 
of  the  lingual  and  hypoglossal  nerves,  the  course  of  the  ranine 
and  sublingual  arteries,  and  the  site  of  the  sublingual  gland 
and  Wharton's  duct  may  be  seen.  9.  Internal,  and  «,  ex- 
ternal layers  of  fibres  of  the  genio-hyo-glossus.  E.  Longitu- 
dinal, and  z,  inferior  transverse  fibres  of  the  lingualis,  H, 
genio-hyoid,  and  ©,  mylo-hyoid  muscles. 

;. — Anterior  belly  of  the  digastric. 

K. — Levator  palati,  A,  superior,  M,  middle,  and  N,  inferior  constric- 
tors of  the  pharynx,   s.  Longitudinal  fibres  of  the  oesophagus. 


DESCRIPTION    OF    THE    PLATES.  XIX 

O. — Trachea,     *.  Rings  of  the  trachea. 

n.  Larynx.  x.  Cricoid,  and  (x,  thyroid  cartilages.  ».  Epiglottis. 
£.   Ventricle  of  the  larynx,     o.  Arytsenoideus  muscle. 

p. — Isthmus  of  the  thyroid  gland. 

Z. — Wharton's  duct.     T.   Sublingual  gland. 

r. — Tongue,  m.  Circumvallate,  and  p,  fungiform  papillae,  a-.  Root 
of  the  tongue. 

*  — Palate,  t.  Soft  palate,  v.  Mucous  membrane  of  the  hard  pal- 
ate.    <f>.   Incisive  papilla. 

X. — Roof  of  the  pharynx,  x-  Pharyngeal  orifice  of  the  Eustachian 
tube.  -^.  Mucous  glands  of  the  roof  of  the  pharynx. 
a).   Eustachian  eminence. 

y. — Left  posterior  nares.     n.  Membrane  of  the  nasal  septum. 

AA. — Dura  mater,  an.  Anterior,  and  bb,  posterior  part  of  the  falx 
cerebri,  cc.  Tentorium  cerebelli.  dd.  Posterior  end  of  the 
superior  longitudinal  sinus,  ee.  Superior  petrosal  sinus. 
ff.  Sigmoid  portion  of  the  lateral  sinus. 

BB. — Dura  mater  of  the  spinal  cord. 

CC. — Vertebral  artery,    gg.  Its  first,  hh,  second,  and  ii,  third  flexures. 

DD. — Inferior  thyroid  artery. 

EE. — Common  carotid. 

FF. — External  carotid. 

GG. — Superior  thyroid  artery. 

HH. — Lingual  artery,  kk.  Sublingual  artery.  //.  End  of  the 
ranine  artery. 

II. — Facial  artery. 

KK. — Ascending  pharyngeal  artery,  mm.  Pharyngeal,  and  nn,  ba- 
silar branches. 

(IiL.) — Internal  maxillary  artery,  oo.  Arteries  of  the  nasal  sep- 
tum,    pp.  Descending  palatine  artery. 

MM. — Internal  carotid,  qq.  Cowper's  flexure,  which  is  sometimes 
found.  rr.  Its  first,  ss,  second,  tt,  third,  and  uu,  fourth 
flexures,  vv.  Posterior  communicating  artery,  uno.  Anterior 
choroid  artery,  xx.  Middle  cerebral  or  Sylvian  artery. 
yy.  Anterior  cerebral  artery,  zz.  Ethmoidal  branch  of  the 
ophthalmic  artery,  anastomosing  with  the  nasal  branches  of 
the  internal  maxillary. 

NN. — Trunk  of  the  vertebral  vein,  which  receives  the  cervical  part 
of  the  vertebral  sinus,  (OO),  between  the  fifth  and  sixth 
cervical  vertebra.     PP. — Vertebral  vein  accompanying  the 


XX         DESCRIPTION  OF  THE  PLATES. 

vertebral  artery  through  the    vertebral   foramina  and  con- 
nected  by  many  transverse  branches  with  the  vertebral  sinus. 

QQ. — Anastomosis  of  the  superior  and  inferior  thyroid  arteries. 

I. — Olfactory  nerve.  1.  Olfactory  filaments  of  the  nasal  septum  in- 
closed in  fibrous  sheaths. 

II. — Optic  nerve. 

III.— Motor  oculi  nerve. 

IV. — Pathetic  nerve. 

V. — Trifacial  nerve. 

First  division.     2.  Nasal  nerve. 

Second  division.     3.  Nasal  nerves.     4.  Branch  to  the  hard  pal- 
ate, passing  through  the  anterior  palatine  canal. 
5.  Pharyngeal  nerves. 
Third  division.     6.  Lingual  nerve.     7.  Lingual  branches. 

VI. — Abducens  nerve. 

VII. — Facial  nerve. 

VIII. — Auditory  nerve. 

IX. — Glosso- pharyngeal  nerve.  8.  The  petrous  ganglion.  9.  Junc- 
tion with  the  jugular  branch  of  the  superior  cervical  gang- 
lion. 10.  Branch  joining  the  superior  pharyngeal  branch 
of  the  vagus.  11.  Pharyngeal  branches.  12.  Lingual 
branch.  13.  Branches  going  to  the  circumvallate  papillae. 
14.  Branches  supplying  the  mucous  membrane  between  the 
circumvallate  papillae  and  the  epiglottis. 

3L — Pneumogastric  nerve.  15.  Superior  vagal  ganglion.  16.  Junc- 
tion with  the  jugular  branch  of  the  superior  cervical  gang- 
lion. 17.  Recurrent  branch  of  the  vagus.  18.  Its  lesser 
division  going  to  the  occipital  sinus,  and  the  greater  branch, 
19,  going  to  the  sigmoid  sinus.  20.  Superior  pharyngeal 
branch.  21.  Inferior  vagal  ganglion,  or  ganglion  of  the 
Trunk.  22.  Inferior  pharyngeal  branch  passing  to  the  pha- 
rynx between  the  internal  and  external  carotids.  23.  Supe- 
rior laryngeal  nerve.  24.  External  branch.  25.  Its  junc- 
tion with  the  sympathetic  nerve.  26.  Internal  branch  of 
the  superior  laryngeal  nerve.  27.  Branches  distributed  to 
the  raucous  membrane  of  the  larynx  and  epiglottis.  28. 
Junction  with  the  inferior  laryngeal  nerve.  29.  Vagus  nerve 
in  the  neck.  30.  Inferior  laryngeal  nerve.  31.  Its  inoscu- 
lation with  the  sympathetic.  32.  Oesophageal  branches. 
33.  Tracheal  branches.     34.  Laryngeal  branch. 


DESCRIPTION  OF  THE  PLATES.        XXI 

XI. — Spinal  accessory  nerve.  35.  Its  internal,  and  36,  external 
divisions. 

XII. — Hypoglossal  nerve.  37.  Its  inosculation  with  the  first  cervical 
nerve  and  superior  cervical  ganglion.  XII*. — Branches  of 
the  hypoglossal  to  the  genio-hyo-glossus  and  genio-hyoid 
muscles. 

XIII. — XIX. — Seven  superior  cervical  nerves.  38.  Their  anterior,  and 
39,  their  posterior  roots.  40.  Ganglia  on  the  posterior  roots 
of  the  cervical  nerves.  41.  Anterior  division  of  the  first, 
second,  third,  and  fourth  cervical  nerves.  42.  Communi- 
cating branches  of  these  nerves,  constituting  the  cervical 
plexus.  43.  Principal  root  of  the  phrenic  nerve,  coming 
from  the  anterior  division  of  the  fourth  cervical  nerve. 

XX. — Superior  cervical  ganglion.  44.  Carotid  nerve.  45.  Its  internal 
inferior  branch.  46.  Carotid  plexus.  47.  Cavemosus  plexus, 
from  which  are  given  off  branches  to  the  abdncens  (48),  to 
the  ophthalmic  division  of  the  fifth  (49),  and  to  the  cerebral 
and  ophthalmic  arteries  (50).  51.  Jugular  nerve,  forming  a 
junction  with  the  glossopharyngeal  and  vagus  nerves.  52. 
Nerve  uniting  the  hypoglossal  and  first  cervical  nerves.  53. 
Trunk  inosculating  with  the  cervical  plexus.  54.  Junction 
of  the  superior  cervical  and  inferior  vagal  ganglia.  55.  Sym- 
pathetic trunk  to  the  external  carotid,  which  is  often  com- 
posed of  two  or  three  branches.  56.  Superior  part  of  the 
trunk,  from  which  branches  go  to  the  external  carotid  (57), 
and  to  the  carotid  plexus  (58).  (59.)  Inferior  part  of  the 
trunk,  which  gives  branches  to  the  facial  (60),  lingual  (61), 
and  thyroid  arteries  (62).  63.  Branch  going  to  the  carotid 
ganglion  (64),  which  sends  very  delicate  branches  to  the 
common  carotid  artery  (65).  66.  Branches  to  the  external 
branch  of  the  superior  laryngeal,  and  67,  to  the  phrenic 
nerves.  68.  Superior  cardiac  nerve,  arising  from  the  cer- 
vical sympathetic  trunk  by  several  roots.  69.  Its  commu- 
nication with  the  inferior  laryngeal  nerve.  70.  Middle 
cardiac  nerve,  uniting  with  the  superior  cardiac  nerve. 

XXI. — Upper  portion  of  the  first  thoracic  ganglion.  71.  Sympathetic- 
branches  to  the  vertebral  artery.  72.  Sympathetic  plexus 
on  the  vertebral  artery.  73.  Sympathetic  plexus  on  the 
inferior  thyroid  artery. 


XX11  DESCRIPTION    OP    THE    PLATES, 


PLATE   IY. 
Fig.  I. 

This  diagram  shows  the  trifacial,  lateral  nasal,  and  palatine  nerves, 
the  spheno- palatine  and  otic  ganglia,  and  the  facial  nerve  in  the  facial 
canal,  seen  from  the  inside. 

The  skull  and  posterior  part  of  the  head,  parts  of  the  neck,  and 
most  of  the  petrous  portion  of  the  temporal  and  the  sphenoid  bones 
are  removed  ;  the  facial  canal  and  tympanic  cavity  are  opened  to 
view,  the  internal  carotid  artery  and  carotid  canal,  the  cartilaginous 
portion  of  the  Eustachian  tube,  roof  of  the  pharynx  and  levator 
palati  muscle,  the  nasal  septum,  and  posterior  part  of  the  hard 
palate  are  cut  away  ;  the  pterygo-palatine  fossa  and  canals  are 
shown,  and  the  mucous  membrane  of  the  nose  is  partly  removed. 

Therefore  the  internal  auditory  meatus,  the  facial  canal,  the  osseous 
portion  of  the  Eustachian  tube  and  the  tympanic  membrane,  the  ear 
ossicles  and  their  muscles,  the  course  of  the  facial  nerve  through  the 
petrous  portion  of  the  temporal  bone,  the  inner  surface  of  the  trunk 
of  the  trifacial  nerve  and  its  ganglion,  with  its  first,  second,  and  third 
divisions,  the  otic  and  spheno-palatine  ganglia,  the  nerves  of  the  palate, 
and  the  lateral  wall  of  the  nose  with  the  distribution  of  the  nerves  of 
the  first  and  fifth  pairs  to  its  mucous  membrane  are  shown. 
A. — Petrous  portion  of  the  temporal  bone.     a.   Bottom  of  the  inter- 
nal auditory  meatus,  and  b,  interior  of  the  facial  canal,     c. 
Superior  margin,  and  d,  inner  surface  of  the  petrous  portion 
of  the  temporal  bone. 
B. — Sphenoid  bone.     e.  Foramina  spinosum,y,  ovale,  and  g,  rotun- 
dum  opened   from  within,     h.   Pterygoid  process,  with   the 
internal    plate   partly   removed,     i.  Hamular    process,     k. 
Inner  extremity  of  the  lesser  wings.     /.  Optic  foramen. 
C. — Lower  part  of  the  vertical  plate  of  the  frontal  bone.     m.  Frontal 

sinus. 
D. — Ethmoid    bone.     n.    Posterior    ethmoidal    cells,     o.    Cribriform 
plate,     p.   Anterior  ethmoidal  foramen,     q.  Left  nasal  fossa. 
E. — Left  nasal  bone. 

F. — Palate  process  of  the  superior  maxillary  bone. 
Gr. — Ramus  of  the  inferior  maxillary  bone.     r.  Angle  of  the  inferior 
maxillary  bone. 


PLATE    IV. 


.. 


*tm. 


DESCRIPTION    OF    THE    PLATES.  XXlii 

H. — Tensor  palati  muscle  turned  forward. 
I. — Interna]  pterygoid  muscle. 
K. — Tensor  tympani,  and  L,  stapedius  muscles. 
31. — Upper  end  of  the  external  carotid  artery. 
N. — Temporal  artery. 

O. — Internal  maxillary  artery,     s.   Inferior   dental  artery.     /.  Mid- 
dle meningeal  artery.      u.    Descending  palatine  artery,     v. 
Nasal  artery  cut. 
I*. — Posterior  auricular  artery. 

Q. — Dura  mater,  upper  surface  of  the  petrous  portion  of  the  temporal 
bone,  and  the  trifacial,  pathetic,  motor  oculi  and  abduceiis 
nerves.  K. — Inner  surface  of  the  tympanic  membrane,  and 
the  ear  ossicles.  w.  The  head,  x,  neck,  and  y,  the  manubrium 
of  the  malleus,  z.  The  incus,  a.  Stapes. 
S. — Lateral  wall  of  the  nasal  cavity.  &.  The  superior,  y,  middle, 
and  £,  inferior  turbinated  bones,  t.  The  superior,  £,  mid- 
dle, and  n,  inferior  meatuses  of  the  nose.  S.  Lateral  carti- 
lage, and  «,  ala  of  the  nose.  x.  Mucous  membrane  covering 
the  superior  and  upper  part  of  the  middle  turbinated  bones 
removed  to  show  the  course  of  the  olfactory  filaments  through 
the  grooves  of  the  ethmoidal  turbinated  bones,  x.  Mucous 
membrane  of  the  anterior  inferior  regions  of  the  nares  is 
removed,  showing  the  distribution  of  the  nasal  branches  of 
the  fifth  nerve.  /*.  Mucous  membrane  of  the  inferior  meatus. 
».  Mucous  glands. 
T. — Mucous  membrane  of  the  hard  and  soft  palate. 
U. — The  tongue.     £.   Lingual  papilla?,     o.  Glands  at  the  root  of  the 

tongue. 
V. — Parotid  gland. 

(I.) — Olfactory  nerve.     1.  Olfactory  filaments  of  the  wall  of  the  nose 
which  have  fibrous  sheaths  and  run   through  grooves  in  tin 
upper  and  middle  turbinated  bones,  forming  a  network  aim 
sending  delicate  branches  to  the  mucous  membrane. 
II. — Optic  nerve. 
III. — Motor  oculi  nerve. 
IV. — Pathetic  nerve. 

V. — Trifacial  nerve.  2.  Common  trunk.  3.  Its  lesser,  and  4,  its 
greater  roots.  5.  Semilunar  ganglion,  (j.  First  or  ophthal- 
mic division  of  the  fifth  nerve.  7.  Nasal  nerve.  B. 
Branch  to  the  nasal  septum  severed  (vid.  Plate  III.,  2).  9. 
Branch  to   the  lateral  surface  of   the  nares.      10.  External 


XXIV  DESCRIPTION    OF    THE    PLATES. 

branch  (vid.  Plate  VIII.,  7).  11.  Second  or  superior  maxil- 
lary division  of  the  fifth.  12.  Naso-palatine  nerve.  13. 
Posterior  palatine  nerves.  14.  The  anterior  palatine  nerve. 
15.  Superior,  and  16,  inferior  nasal  nerves.  17.  Spheno- 
palatine ganglion  (Meckel's).  18.  Greater  deep  petrosal 
nerve.  19.  Greater  superficial  petrosal.  20.  Vidian  nerve. 
21.  Ascending  branches,  and  22,  branch  from  the  ganglion 
to  the  nose.  23.  Third  or  inferior  maxillary  division  of  the 
fifth.  24.  Recurrent  branch  piercing  the  otic  ganglion  and 
accompanying  the  middle  meningeal  artery  within  the 
cranium  (rid.  Plate  II.,  27).  25.  Auriculotemporal  nerve, 
arising  by  two  roots,  between  which  passes  the  middle  men- 
ingeal artery.  2(3.  Inferior  dental  nerve.  27.  Lingual 
nerve.  28.  Junction  of  the  chorda  tympani  and  lingual 
nerves.  29.  Internal  pterygoid  nerve.  30.  Branches  to 
the  tensor  palati,  and  31,  to  the  tensor  tympani  muscles, 
coming  from  the  pterygoid  nerve  and  piercing  the  otic  gang- 
lion. 32.  Otic  ganglion.  33.  Lesser  superficial  petrosal, 
coming  from  the  tympanic  nerve.  34.  Sympathetic  root 
of  the  otic  ganglion.  35.  Branch  to  the  tensor  tympani 
leaving  the  otic  ganglion.  36.  Branch  proceeding  to  the 
auriculotemporal  nerve. 

VI. — Abducens  nerve. 

VII. — Facial  nerve.  37.  Genu  of  the  facial  nerve.  38.  Greater 
superficial  petrosal  nerve.  39.  Junction  with  the  lesser 
superficial  petrosal  nerve,  which  arises  from  the  tympanic 
nerve.  40.  Branch  to  the  stapedius  muscle.  41.  Chorda 
tympani. 

Fig.  II. 

Showing,  from  behind,  the  course  of  the  facial,  glossopharyngeal, 
pneumogastric,  spinal  accessory,  and  hypoglossal  nerves  in  the 
cranial  bones,  and  of  the  auricular  branch  of  the  vagus  in  the 
petrous  portion  of  the  right  temporal  bone. 

The  occiput  of  the  right  side  of  the  head  is  removed  by  a  transverse 
section,  opening  the  condyloid  and  posterior  lacerated  foramina,  and 
the  facial  canal  and  auricular  fissure  from  behind. 

Therefore  the  course  of  the  hypoglossal,  spinal  accessory,  vagus 
and  glosso-pharyngeal  nerves  through  the  foramina  of  the  skull,  the 
ganglia  of  the  vagus  and  glosso-pharyngeal  nerves,  the  auricular 
branch  of  the  vagus  and  its  junction  with  the  facial  nerve  are  seen. 


DESCRIPTION  OF  THE  PLATES.        XXV 

A. — Occipital  bone.     <i.  Basilar  process.     6.  The  condyle,     c.  Anterior 

condyloid  foramen. 

B. — Body  of  the  sphenoid  bone  covered  by  dura  mater. 

C — Petrous  portion  of  tbe  temporal  bone.  </.  Its  superior  internal 
margin,  e.  Inner  surface,  f.  Internal  auditory  meatus,  g. 
Cavity  of  the  tympanum,  It,  mastoid  cells,  and  i,  posterior 
part  of  the  facial  canal  from  behind,  k.  ('anal  for  the  chorda 
tympani.  /.  Auricular  fissure.  m.  Mastoid  process,  u. 
Styloid  process,  o.  Stylo-mastoid  foramen,  p.  Upper  part 
of  the  bead  of  the  malleus.  7.  The  body,  and  r,  the  short 
process  of  the  incus. 

D. — Posterior  surface  of  the  ear. 

E. — Skin  and  adipose  tissue. 

F. — Sterno-cleido-mastoid  muscle,  cut  perpendicularly. 

G. — Posterior  belly  of  the  digastric  muscle,  also  divided. 

H. — Posterior  surface  of  the  roof  of  the  pharynx,  a.  Acinous  mucous 
glands  of  the  pharynx,  t.  Superior  constrictor  muscle  of 
the  pharynx. 

I. — Internal  carotid. 

K. — Internal  jugular  vein,  cut  off  above  so  that  the  course  of  the 
auricular  branch  of  the  vagus  nerve  may  be  seen. 

L. — Occipital,  and  M,  posterior  auricular  arteries. 

VII. — Facial  nerve.  1.  Chorda  tympani.  2.  Posterior  auricular 
nerve.  3.  Small  branches  going  to  the  posterior  belly  of  the 
digastric  muscle. 

VIII. — Auditory  nerve. 

IX. — Glossopharyngeal  nerve.  4.  The  petrous  ganglion.  5.  Branch 
joining  the  auricular  branch  of  the  vagus.  6.  Pharyngeal 
branches  of  the  glosso-pharyngeal  nerve. 

X. — Pneumogastric  nerve.  7.  Superior  vagal  ganglion.  8.  Recur- 
rent branch  of  the  vagus,  divided  transversely.  9.  Auricular 
branch  of  the  vagus.  10.  Its  communication  with  the  facial 
nerve  in  the  facial  canal.  11.  Its  communication  with  the 
posterior  auricular  nerve.  12.  Its  auricular  branches.  13. 
Inferior  vagal  ganglion. 

XI. — Spinal  accessory  nerve.  14.  Its  internal,  and  15,  its  external 
divisions. 

XII. — Hypoglossal  nerve. 

XIII. — Carotid  nerve  and  the  upper  part  of  the  superior  cervical 
ganglion. 


xxvi  DESCRIPTION    OF    THE    PLATES. 


PLATE    Y. 

ILLUSTRATION  OF  CRANIAL  AND  CERVICAL  NERVES,  THE 
NERVES  ACCOMPANYING  THE  CAROTID  AND  VERTEBRAL 
ARTERIES,  BOTH  WITHIN  AND  OUTSIDE  OF  THE  CRANIUM, 
AND  THE  SPINAL  CORD  SEEN  FROM  THE  OUTSIDE. 

This  plate  shows,  firstly,  the  origin  of  the  cranial  and  cervical 
nerves  of  the  right  side,  with  the  exception  of  the  first  and  sixth 
pairs  ;  secondly,  the  course  of  the  cervical  nerves  between  the  cervical 
vertebrae,  the  spinal  ganglia,  the  breaking  up  of  the  nerves  into  their 
anterior  and  posterior  divisions,  and  their  inosculations  amongst 
themselves  and  with  the  superior  cervical  ganglion  ;  then  the  course 
and  part  of  the  distribution  of  the  third,  fourth,  fifth,  ninth,  tenth, 
eleventh,  and  twelfth  pairs  of  nerves  outside  of  the  cranium,  and 
the  roots  of  the  ophthalmic  and  spheno-palatine  ganglia  and  the 
sympathetic  plexuses  on  the  vertebral  and  internal  carotid  arteries. 

To  show  these  parts  the  scalp,  occipital,  frontal,  parietal,  mastoid 
and  petrous  portions  of  the  temporal,  the  greater  and  lesser  wings  of 
the  sphenoid,  the  malar  and  posterior  portions  of  the  inferior  maxillary 
bones  of  the  right  side,  the  spinous  and  transverse  processes,  and  the 
arches  of  the  cervical  vertebrae,  together  with  the  skin  and  superficial 
muscles  of  the  neck,  the  muscles  and  vessels  of  the  face  and  temples, 
and  the  thyroid  and  salivary  glands  are  removed  ;  the  intervertebral, 
condyloid,  and  posterior  lacerated  foramina,  spinal  canal,  internal 
auditory  meatus,  carotid  canal,  Eustachian  tube,  pterygo-palatine 
fossa,  Vidian  canal  and  the  antrum  of  Highmore  are  opened  ;  the 
right  half  of  the  cerebellum  and  cerebrum,  together  with  the  corpus 
striatum,  is  removed  ;  while  the  spinal  cord,  medulla  oblongata,  pons 
Varolii,  crus  cerebri,  right  optic  thalamus  and  corpora  quadrigemina 
remain  intact. 

A. — G. — Cervical  vertebrae  from  the  first  to  the  seventh,  a.  Left 
portion  of  the  spinous  processes,  b.  Right  transverse  pro- 
cesses, c .  Anterior,  and  d,  posterior  roots  of  the  transverse 
processes. 
JJ. — Occipital  bone.  e.  Its  tabular  portion.  /.  External  occipital 
protuberance,  g.  Right  condyle,  h.  Anterior  condyloid 
foramen,     i.  Posterior  lacerated  foramen. 


PLATE    V. 


DESCRIPTION    OF    THE    PLATES.  XXV11 

I.— Petrous  portion  of  the  right  temporal  bone.  k.  The  posterior, 
/,  external,  and  m,  superior  semicircular  canals,  n.  Cochlea. 
o.  Fenestra  ovalis,  and  p,  fenestra  rotunda,  q.  Base  of  the 
styloid  process. 

K. — Body  of  the  sphenoid  bone.  r.  Clivus  Blumenbachii.  s.  In- 
ternal plate  of  the  pterygoid  process. 

L. — Parietal  bone  sawed  through  near  the  sagittal  suture. 

M. — Frontal  bone. 

N. — Superior  maxillary  bone.     t.  Antrum  of  High  more. 

O. — Inferior  maxillary  bone. 

P. — Molar,  and  Q,  bicuspid  teeth  of  the  upper  jaw. 

R. — Right  inferior  canine  tooth. 

S. — Greater  cornu  of  the  hyoid  bone. 

T. — The  trapezius,  U,  splenitis,  V,  biventer  cervicis,  W,  Semi- 
spinalis  colli,  X,  interspinals,  Y,  rectus  capitis  posticus 
major,  and  Z,  minor  muscles  of  the  left  side. 

AA. — Right  rectus  capitis  anticus  major  muscle. 

BB,  and  CC. — Inferior,  DD,  middle,  and  EE,  superior  con- 
strictor muscles  of  the  pbarynx. 

FF. — Stylo-pharyngeus  muscle. 

GG. — The  stylo-hyoid,  HH,  genio-hyo-glossus,  JJ,  genio-hyoid, 
and  KK,  mylo-hyoid  muscles.  EL. — The  hyo-glossus 
muscle,  partly  cut  away  to  show  the  course  of  the  lingual 
artery  and  lingual  branch  of  the  glosso-pharyngeal  nerve. 

MM. — The  thyro-hyoid,  and  NN,  crico-thyroid  muscles. 

OO. — Levator  palati  muscle.  PP. — Tendon  of  the  tensor  palati 
muscle. 

QQ. — Levator  anguli  oris  muscle. 

KR. — The  levator  palpebral  superioris,  SS,  superior,  and  TT,  in- 
ferior recti,  and  UU,  inferior  oblique  muscles  of  the  eye. 

W.— The  eyeball. 

WW. — The  upper,  and  XX,  lower  lids,  cut  through  perpendicu- 
larly. 

YY. — The  tongue,  u.  Fungiform  papillse.  v.  Mucous  membrane 
of  the  cheek. 

ZZ. — The  larynx.     A. — Trachea. 

B. — Oesophagus. 

r. — Eustachian  tube. 

A. — Common  carotid. 

E. — External  carotid. 


XXvili  DESCRIPTION    OF    THE    PLATES. 

Z. — Superior  thyroid  artery,  w.  Superior  laryngeal  artery,  x.  Thy- 
roid branches  severed,     y.  Muscular  branches. 

H. — Lingual  artery. 

©. — Origin  of  the  facial  artery. 

I. — Ascending  pharyngeal  artery. 

K. — Internal  maxillary  artery,  z.  Posterior  dental  artery,  a.  Infra- 
orbital artery.  /?.  Descending  palatine  artery,  y.  Nasal 
artery. 

A. — Internal  carotid.  S\ — Its  first,  t,  second,  £,  third,  and  »,  fourth 
flexures. 

M. — Ophthalmic  artery. 

N. — The  posterior  communicating,  O,  anterior  choroid,  n,  middle 
cerebral,  and  P,  anterior  cerebral  arteries  of  the  right  side. 
2.  Anterior  cerebral  artery  of  the  left  side. 

T. — Vertebral  artery.  $.  Its  first,  i,  second,  and  x,  third  flexures, 
x.  Spinal  branches,  /t*.  The  right,  and  v,  left  posterior 
inferior  cerebellar  arteries.  £.  Internal  auditory  artery, 
o.  Right  superior  cerebellar  artery,  it.  The  right,  and  p,  left 
posterior  cerebral  arteries.     <r.  Inferior  thyroid  artery. 

T. — Dura  mater  of  the  spinal  cord. 

<j>. — Tentorium  cerebelli.     t.  Superior  petrosal  sinus. 

x — Dura  mater  of  the  brain. 

•V. — Cervical  spinal  cord. 

n. — Medulla  oblongata,     y.  Stria?  medullares.    <p.  Sinus  rhomboidalis. 

AA. — Cerebellum.  ^.  Inner  surface  of  the  left  hemisphere.  •*.  Arbor 
vita?.  &>.  Fourth  ventricle,  aa.  Valve  of  Vieussens,  or  su- 
perior medullary  velum.  &%.  The  inferior,  yy,  middle,  and 
JS\  superior  cerebellar  peduncles,     tt.  Right  side  of  pons 

BB. — Right  cms  cerebri. 

rr. — Corpora  quadrigemina. 

A  a.  Right  optic  thalamus. 

ee. — Fornix.  ££.  Right  cms  of  the  fornix.  «u.  Foramen  of  Monro. 
99-.   Body  of  the  fornix,     u.  Septum  lucidum. 

ZZ. — Corpus  callosum  divided  longitudinally  through  the  centre, 
xx.  Its  genu,  XA,  body,  and  fx/x,  splenium. 

hh. — Inner  surface  of  the  left  cerebral  hemisphere,  w.  The  frontal, 
oo,  parietal,  and  irir,  occipital  lobes,     pp.  Gyrus  fornicatus. 

II. — Optic  nerve.  1.  Its  origin  from  the  optic  thalamus.  2.  Optic 
tract.     3.  Orbital  portion  of  the  optic  nerve. 


DESCRIPTION    OF    THE    PLATES.  XXIX 

III. — Motor  oculi.  4.  Superior  branch  to  the  superior  rectus  and 
levator  palpebrae  superioris  muscles.  5.  Inferior  branch. 
6.  Motor  root  of  the  ophthalmic  ganglion.  7.  Branch  to  the 
inferior  oblique  muscle. 

IV. — Pathetic  nerve.  8.  Its  origin.  9.  Course  of  the  pathetic  nerve 
above  the  pons  and  external  to  the  cms  cerebri.  10.  Its 
course  along  the  upper  border  of  the  ophthalmic  division  of 
the  trifacial  nerve. 

V.  Trifacial  nerve.  11.  Its  lesser,  and  12,  greater  roots.  13.  Semi- 
lunar ganglion.  14.  First  or  ophthalmic  division  of  the 
fifth.  15.  Supraorbital  nerve.  16.  Lachrymal  nerve  cut 
away.  17.  Nasal  nerve.  18.  Sensory  root  of  the  ophthalmic 
ganglion.  19.  Long  ciliary  nerves.  20.  Ophthalmic  gang- 
lion. 21.  Its  sympathetic  root.  22.  Short  ciliary  nerves. 
23.  The  superior,  and  24,  inferior  fasciculi  of  ciliary 
nerves.  25.  Second  division  or  superior  maxillary  nerve. 
26.  Subcutaneous  malae  nerve  severed.  27.  Infraorbital 
nerve.  28.  Posterior  dental  nerves.  29.  Anterior  dental 
nerve  severed.  30.  The  iuferior  palpebral,  lateral  nasal,  and 
superior  labial  nerves.  31.  Naso-palatine  nerve.  32.  Spheno- 
palatine ganglion.  33.  Greater  superficial  petrosal  nerve. 
34.  Greater  deep  petrosal  nerve.  35.  Posterior  superior 
nasal  nerve.  36.  Palatine  nerves.  37.  Third  division  or 
inferior  maxillary  nerve.  38.  Auriculotemporal  nerve.  39. 
Masseter  nerve.  40.  Posterior  deep  temporal  nerve.  41. 
Buccal  nerve.  42.  Inferior  dental  nerve.  43.  Lingual  nerve, 
the  lingual  part  of  it  being  reflected  to  show  the  distribution 
of  the  hypoglossal  nerve.     44.  Lingual  branches. 

VI. — Abducens  nerve  severed. 

VII. — Facial  nerve.  45.  Genu  of  the  facial  nerve.  46.  Its  junction 
with  the  greater  superficial  petrosal  nerve. 

VIII. — Auditory  nerve. 

IX. — Glosso-pharyngeal  nerve.  47.  Petrous  ganglion.  48.  Tym- 
panic nerve.  49.  Branch  joining  the  carotid  nerve.  50. 
Branches  to  the  fenestra  rotunda,  and  51,  to  the  fenestra 
ovalis.  52.  Branch  going  to  the  Eustachian  tube.  53. 
Lesser  superficial,  and  54,  lesser  deep  petrosal  nerves.  55. 
Branches  uniting  with  the  branches  of  the  superior  cervical 
ganglion,  and  with  branches  from  the  iuferior  vagal  ganglion. 
56.    Carotid   plexus.      57.    Branches    running   between  the 


XXX        DESCRIPTION  OF  THE  PLATES. 

internal  and  external  carotids  to  the  carotid  ganglion.  58. 
Pharyngeal  branches.  59.  Branches  to  the  stylo-pharyngeus 
muscle.     60.  Lingual  branches. 

X. — Pneumogastric  nerve.  61.  Superior  vagal  ganglion.  62.  Branch 
to  the  carotid  plexus.  63.  Inferior  vagal  ganglion.  64. 
Superior  laryngeal  nerve.  65.  External  branch  to  the  crico- 
thyroid muscle.  66.  Junction  of  this  branch  with  a  filament 
from  the  superior  cervical  ganglion.  67.  Internal  branch  of 
the  superior  laryngeal  nerve.  68.  Trunk  of  the  vagus  in  the 
neck.  69.  Inferior  or  recurrent  laryngeal  nerve,  sending 
branches  to  the  oesophagus,  trachea,  and  larynx. 

XI. — Spinal  accessory  nerve.  70.  Its  spinal,  and  71,  cranial  roots. 
72.  Course  of  the  spinal  root  between  the  roots  of  the  pos- 
terior division  of  the  first  cervical  nerve.  73.  Its  internal 
division,  uniting  with  the  trunk  of  the  vagus.  74.  Its  ex- 
ternal division. 

XII. — Hypoglossal  nerve.  75.  Its  roots  passing  over  the  vertebral 
artery.  76.  A  branch  joining  the  first  cervical,  and  77,  the 
vagus  nerves.  78.  Descendens  noni  branch.  79.  Thyro- 
hyoid branch.  80.  Branch  to  the  genio-hyoid,  and  81,  the 
stylo-glossus  muscles.  82.  Branches  to  the  hyo-glossus,  and 
83,  the  genio-hyo-glossus  and  the  muscles  of  the  tongue 
proper. 

XIII. — First  cervical  nerve.  84.  Its  posterior  root,  which  is  crossed 
by  the  spinal  accessory  nerve.  85.  The  posterior  division 
cut  away.     86.  Anterior  division.     87.  Muscular  branch. 

XIV. — Second  cervical  nerve.  88.  Posterior  root.  89.  Spinal  gang- 
lion. 90.  Posterior  division  severed.  91.  Anterior  division. 
92.  Branch  joining  the  first  cervical  nerve  and  superior  cer- 
vical ganglion.  93.  Branch  to  the  rectus  capitis  anticus 
major  muscle.  94.  Descending  communicating  branch.  95. 
Communicans  noni  branch. 

XV. — Third  cervical  nerve.  96.  The  posterior  root  divided  and 
reflected  to  show  the  course  of  the  spinal  root  of  the  spinal 
accessory  nerve.  97.  Branch  joining  the  posterior  root  of 
the  fourth  cervical  nerve.  98.  Spinal  ganglion.  99.  Pos- 
terior division  severed.  100.  Anterior  division.  101.  Junc- 
tion with  the  superior  cervical  ganglion.  102.  Communicans 
noni  branch.     103.  Ansa  hypoglossi. 


XVII. — Fifth  cervical  nerve. 
XVIII. — Sixth  cervical  nerve. 
XIX. — Seventh  cervical  nerve. 


DESCRIPTION    OF    THE    PLATES.  X  \  \  I 

XVI. — Fourth  cervical  nerve.  104.  Posterior  root  divided.  1".">. 
Its  junction  with  tbe  posterior  rool  of  the  fifth  cervical 
nerve.  106.  Spinal  ganglion.  107.  Posterior  division 
severed.  108.  Anterior  division.  109.  Branch  to  the 
longus  colli  muscle.  110.  Trunk  of  the  anterior  division 
severed. 

f  111.  Posterior  root.  112.  Spinal 
ganglion.  113.  Posterior  division 
severed.  114.  Anterior  division 
severed.  115.  Roots  of  the 
phrenic  nerve. 
XX. — Posterior  root  of  the  eighth  cervical  nerve. 

XXI. — Superior  cervical  ganglion.  116.  Sympathetic  branches  to 
the  carotid  ganglion.  117.  Carotid  ganglion.  118.  Fila- 
ments to  the  common  and  external  carotid  arteries.  119. 
Branch  to  the  carotid  plexus.  120.  Superior  external 
branch  of  the  carotid  nerve,  from  which  the  greater  deep 
petrosal  nerve  is  given  off.  121.  Inferior  internal  branch 
of  the  carotid  nerve.  122.  Sympathetic  nerves  on  the 
internal  carotid  within  the  cranium. 
XXII. — Cervical  sympathetic  trunk.  123.  Vertebral  branch  from 
the  inferior  cervical  and  superior  thoracic  ganglia.  124. 
Sympathetic  plexus  on  the  vertebral  artery. 


xxxii  DESCRIPTION    OF    THE    PLATES. 


PLATE    YI. 

COURSE  OF  SOME  OF  THE  NERVES  OF  THE  FIFTH  PAIR 
THROUGH  THE  ORBIT,  SUPERIOR  MAXILLARY  BONE  AND 
TEMPORAL  FOSSA  ;  OF  THE  FACIAL  AND  CHORDA  TYM- 
PANI  THROUGH  THE  PETROUS  PORTION  OF  THE  TEM- 
PORAL BONE;  OF  THE  POSTERIOR  DIVISIONS  OF  THE 
CERVICAL  NERVES  IN  THE  MUSCLES  OF  THE  NECK,  AND 
THE  SYMPATHETIC  NERVES  ACCOMPANYING  THE  EXTER- 
NAL CAROTID  ARTERY  AND  ITS  BRANCHES. 

This  plate,  which  shows  the  nerves  of  the  right  side  of  the  head, 
illustrates  first  the  course  of  the  lachrymal  from  the  first,  subcutaneous 
malae  and  infraorbital  from  the  second,  and  the  lingual  and  mylo- 
hyoid from  the  third  division  of  the  fifth  ;  then  the  facial  nerve 
through  the  facial  canal,  and  chorda  tympani  through  the  tympanic 
cavity,  and  the  distribution  of  the  posterior  divisions  of  the  cervical 
nerves  to  the  muscles  of  the  neck,  and  finally  the  sympathetic  plexus 
around  the  external  carotid,  and  the  roots  of  the  submaxillary  gang- 
lion. 

The  skull  is  divided  by  a  perpendicular  section  near  the  sagittal 
suture,  and  the  right  side  of  it,  with  the  dura  mater,  is  removed  ;  the 
greater  wing  of  the  sphenoid,  malar,  and  periorbital  bones,  most  of  the 
right  half  of  the  superior  and  inferior  maxillae,  the  squamous  portion 
and  external  part  of  the  mastoid  process  of  the  temporal  bone,  the 
platysma,  sterno-cleido-mastoid,  sterno-hyoid,  sterno-thyroid,  omo- 
hyoid, and  external  pterygoid  muscles  are  cut  away  ;  and  the  second 
and  third  layers  of  cervical  muscles  are  turned  aside.  Therefore, 
the  following  structures  are  partly  or  wholly  exposed  to  view  :  the 
external  surface  of  the  brain,  the  parts  of  the  eye  adjacent  to  its 
outer  wall,  the  frontal  and  maxillary  sinuses,  the  parts  of  the  oral 
cavity  and  temporal  fossa  adjoining  the  inner  surface  of  the  inferior 
maxillary  bone,  the  tympanic  membrane  and  mastoid  cells,  submaxil  • 
lary  and  thyroid  glands,  larynx,  trachea,  pharynx,  and  oesophagus, 
and  the  muscles  of  the  neck  with  the  vessels  and  nerves. 

A. — G. — Cervical  vertebrae  from  the  first  to  the  seventh,  a.  Trans- 
verse processes,  b.  Superior,  and  c,  inferior  articular  pro- 
cesses. 


PLATE    VI. 


DESCRIPTION    OF    THE    PLATES.  XX.xiii 

H. — Occipital  bone.     d.   Left  upper  part  of  tlie  tabular  portion  of  the 

occipital  bone.     e.  Lower  part  of  the  tabular  portion  of  « »< -< -i - 

pital  bone. 
I. — Temporal    bone.     f.    Mastoid    foramen,      g.   Mastoid   cells,      h. 

Facial  canal,     t.  Styloid  process.     k.  Stylo-mastoid  foramen. 

/.    Membrana   tympani.      m.    Incus,      n.    Malleus,     o.    Eus- 

tachian  tube. 
K. — Sphenoid    bone.     p.    Body.     q.    External    pterygoid    plate,     r. 

Sphenoidal  cells,     s.   Foramen  spinosum.     t.   Foramen  ovale. 

The  foramen  rotundum  is  covered  by  dura  mater. 
L. — Frontal  bone.     u.   Its  orbital,  and  v,  vertical  plates,     w.   Frontal 

sinus. 
M. — Right  parietal  bone,  sawed  through  near  the  sagittal  suture. 
N. — Superior  maxillary  bone.     x.   Inner  wall  of  the  antrum  of  High- 
more,     y.  Canine  tooth,     z.   Bicuspid  teeth,     a.  Molar  teeth. 
O. — Inferior  maxillary  bone,  sawed  through  perpendicularly  near  the 

right  canine  tooth  {&). 
I*. —  Insertion  of  the  sternocleidomastoid  mnscle. 
Q. — Splenitis  capitis   muscle  cut  transversely  near   its   insertion  {y). 

\\.    Trachelo  mastoid    muscle    similarly  cut    ($).     S.    Com- 

plexus  and  biventer  cervicis  muscles,  detached  and  turned 

aside  from  their  origins.     T.  Semispinalis  colli.     U.  Upper 

part  of  the  muPifidus  spina?.     V.  Rectus  capitis    posticus 

major.     W.    Inferior,    and    X,    superior    oblique   muscles. 

Y.  Rectus  capitis  lateralis.     Z.  Intertransversales  muscles. 
A. — Rectus  capitis  anticus  major.     B.  Scalenus  anticus. 
r.  Posterior  belly  of  the  digastric.     A.  Stylo-hyoid.     E.  Styloglossus. 

z.   Internal  pterygoid. 
H.  Anterior  belly  of  the  digastric.     ©.   Mylo-hyoid.     I.  Ceiiiodiyoid. 

K.   Hyo-glossus. 
A.  Thyro  hyoid.     M.  Cricothyroid. 
N    Inferior  constrictor  of  the  pharynx,     e.  Its  cricoid,  and  6,  thyroid 

origins. 
H.   Levator  palpebrae    superioris   and   superior   rectus    muscles.      n 

External    rectus    muscle.      rr.  Inferior    rectus    muscle.       p. 

Inferior  oblique  muscle. 
2.  Eyeball.     T.   Lachrymal  gland. 
T.  Dura  mater.     ».   Lateral  sinus. 
♦.  Cerebrum.     3-.  The  frontal,  t.  parietal,  x,  temporo  sphenoidal,  and 

\,  occipital  lobes,    ju.  External  part  of  the  fissure  of  Sylvias. 

v.   Its  vertical,  and  £,  horizontal  limbs. 


XXXIV  DESCRIPTION    OF    THE    PLATES. 

X.  The  tongue,     o.  Mucous  membrane  of  the  cheek. 

y.  Sublingual  gland.     ft.  Submaxillary  gland.     *Wharton's  duct. 

AA.   Thyroid  gland. 

BB.  Larynx,     ir.  Thyroid  cartilage,     p.  Cricoid  cartilage. 

CC.  (Esophagus. 

DD.  Upper  part  of  the  common  carotid. 

EE.  External  carotid. 

FF.  Superior  thyroid  artery,     a-.  Its  thyroid  branches. 

(jrG.  Lingual  artery. 

Hll.  Facial  artery,     t.  Ascending  palatine  artery,     v.  A  muscular 

branch.     <p.  Submental  artery. 
II.  Occipital  artery,     x-   Descending  cervical  branches.     Y.  Menin- 
geal branch.     &>.   Distribution  of  the  artery  to  the  occiput. 
KK.  Posterior  auricular  artery. 
LL.  Temporal  artery. 

MM.   Internal    maxillary   artery,     aa.   Inferior  dental   artery,     bb. 

Middle  meningeal  artery,     cc.   Posterior  dental  artery,     dd. 

Infraorbital    artery,     ee.    Descending    palatine    and    nasal 

arteries. 

NX.  Internal    carotid,    ff.    Lachrymal   branch    of    the  ophthalmic 

artery,     gg.  Network  of  the  middle  cerebral  arteries. 
OO.  Profunda  cervicis  artery. 

PP.  Vertebral  artery,     hh.  Its  first,  and  k.  second  flexures. 
QQ.    Profunda   cervicis    vein.       BB,    Vertebral    vein.      kk.    Deep 

venous  plexus  of  the  neck. 
SS.  Occipital  vein.     //.  Mastoid  emissary  vein. 
TT.  Lateral  veins  of  the  brain,  emptying  into  the  lateral  sinus. 
UU.  Superior  veins  of  the  brain,  emptying  into  the  superior  longi- 
tudinal sinus. 
W.  Veins  of  the  fissure  of  Sylvius. 

WW.  Ophthalmic  vein.     XX.  Inferior  ophthalmic  vein. 
III. — Motor  oculi  nerve.     1.  Branch  to  the  inferior  oblique  muscle. 
(V.) — Trifacial  nerve. 

First  division.  2.  Supraorbital  nerve.  3.  Lachrymal  nerve. 
4.  Its  superior,  and  5,  inferior  branches.  6.  Second  division 
of  the  fifth.  7.  Subcutaneous  malae  nerve.  8.  Malar  branch 
severed.  9.  Orbital  branch  going  to  the  lachrymal  gland 
and  often  joining  the  inferior  branch  of  the  lachrymal  nerve. 
10.  Infraorbital  nerve.  11.  Posterior  dental  nerve.  12. 
Anterior  dental  nerve.     13.  Trunk  of  the  infraorbital  nerve 


DESCRIPTION  OF  THE  PLATES.       XXXV 

passing  through  the  infraorbilal  canal.  14.  Pharyngeal 
nerve.  15.  Third  division  of  the  fifth.  16.  Buccal  nerve. 
17.  External  pterygoid  nerve.  18.  Anterior  deep  temporal 
nerve.  19.  Posterior  deep  temporal  nerve.  20.  Masseter 
nerve.  21.  Roots  of  the  auriculo-temporal  nerve,  surround- 
ing the  middle  meningeal  artery.  22.  Trunk  of  this  nerve 
divided.  23.  Inferior  dental  nerve,  divided  near  the  inferior 
dental  foramen.  24.  Mylo-hyoid  nerve.  25.  Its  branches 
to  the  mylo-hyoid  and  the  anterior  belly  of  the  digastric 
muscles.  26.  Lingual  nerve.  27.  Junction  of  the  lingual 
and  chorda  tympani  nerves.  28.  Branches  to  the  mouth. 
29.  Branches  to  the  inferior  maxillary  ganglion.  30.  Sub- 
lingual branch.  31.  Lingual  branches.  32.  Submaxillary 
ganglion.  33.  Its  motor  root  coming  from  the  chorda  tympani. 
34.  Its  sympathetic  root.  35.  Branches  to  the  submaxillary 
gland,  and  36,  to  Wharton's  dnct.  37.  Branches  joining  the 
lingual  nerve. 

VII. — Facial  nerve.  38.  Chorda  tympani.  39.  Its  origin,  and  40, 
course  between  the  malleus  and  incus.  41.  Posterior  au- 
ricular nerve.  42.  Branches  to  the  digastric,  and  43,  stylo- 
hyoid muscles.     44.  Trunk  of  the  facial  nerve  divided. 

(X). — Pneumogastric  nerve.  45.  Superior  laryngeal  nerve.  4ti.  In- 
ternal branch.  47.  External  branch,  going  to  the  crico- 
thyroid muscle.  48.  Trunk  of  the  vagus  nerve  in  the  neck. 
4!».  Inferior  or  recurrent  laryngeal  nerve.  50.  (Esophageal 
branches.     51.  Tracheal  branches.     52.  Laryngeal  branch. 

XII. — Hypoglossal  nerve.  53.  Curve  of  the  hypoglossal.  54.  De- 
scendens  noni  branch,  and  55,  branch  to  the  thyro-hyoid 
muscle  divided.  56.  Branch  to  the  genio-hyoid  muscle. 
57.  Branches  to  the  hyo-glossus  muscle.  58.  Branches  to 
the  genio-hyo-glossus  muscle  and  to  the  muscles  of  the 
tongue  proper. 

(XIII.) — First  cervical  nerve.  59.  The  internal  branch  of  the  pos- 
terior division,  sending  filaments  to  the  rectus  capitis  pos- 
ticus major  and  minor,  obliquus  capitis  inferior,  and  com- 
plex US  muscles.  60.  The  external  branch  of  the  posterior 
division,  sending  a  branch  to  the  obliquus  capitis  superior 
and  rectus  capitis  lateralis  muscles,  and  a  branch  over.  (61), 
the  obliquus  capitis  superior  to  the  splenitis  capitis  and 
trachelo-mastoid  muscles. 


XXXVI  DESCRIPTION    OF    THE    PLATES. 

(XIV.) — Second  cervical  nerve.  62.  Anterior  division.  63.  Its 
ascending,  and  64,  descending  inosculating  branches.  65. 
Branch  to  the  rectus  capitis  anticus  major  muscle.  66.  Ex- 
ternal branch  of  the  posterior  division,  going  to  the  trachelo- 
mastoid  and  complexus  muscles.  67.  The  internal  branch  of 
the  posterior  division,  which  sends  brauches,  (68),  to  the  com- 
plexus and  biventer  cervicis  muscles,  and  passes  beneath 
and  within  the  complexus  muscle,  pierces  the  biventer,  and 
becomes  the  occipitalis  major  nerve. 

(XV.) — Third  cervical  nerve.  69.  Anterior  division,  from  which  the 
greater  part  of  the  occipitalis  minor,  (70),  auricularis  magnus, 
(71),  and  superlicialis  colli,  (72),  come.  73.  The  external 
branch  of  the  posterior  division,  going  to  the  scaleni 
muscles,  divided.  74.  The  internal  branch  of  the  posterior 
division,  which  supplies  branches  to  the  complexus,  biventer 
cervicis,  semispinalis  colli  and  multifidus  spinje  muscles,  and 
goes  beneath  and  within  the  complexus  muscle,  pierces  the 
biventer,  and  sends  a  cutaneous  branch  to  the  neck. 

(XVI.) — Fourth  cervical  nerve.  77.  Anterior  division.  78.  Princi- 
pal root  of  the  phrenic  nerve.  79.  The  external  branch  of 
the  posterior  division  divided.  80.  Internal  branch  of  the 
posterior  division.  81.  Muscular  branches.  82.  Descending 
superficial  cervical  nerve. 

(XVII. — XIX.) — The  fifth,  sixth,  and  seventh  cervical  nerves.  83. 
The  anterior  divisions.  84.  The  external  branches  of  the 
posterior  divisions  divided.  85.  The  internal  branches  of 
the  posterior  divisions. 

XX.  — Superior  cervical  ganglion.  86.  Inosculating  branches  with 
the  first  cervical,  and  87,  second  cervical  and  hypoglossal 
nerves.  88.  Sympathetic  nerves  accompanying  the  external 
carotid,  89,  superior  thyroid,  90,  lingual,  91,  facial,  92,  occi- 
pital, and  93,  internal  maxillary  arteries.  94.  Trunk  of  the 
cervical  sympathetic.     95.  Middle  cardiac  nerve  divided. 


PLATE    VII. 


'\\T 


;  :- 


DESCRIPTION    OF    THE    PLATES.  XXXVll 


PLATE   VII. 

THE  NERVES  OF  THE  TEMPORAL  FOSSA,  SUBCUTANEOUS 
MAL.E,  DENTAL,  DE8CENDENS  NONI,  EXTERNAL  BRANCH 
OF  THE  SPINAL  ACCESSORY,  AND  THE  CERVICAL  PLEXUS. 

This  plate  shows  the  right  side  of  the  head  with  the  course  of  the 
subcutaneous  mala?  through  the  malar  foramina,  the  distribution  of 
the  dental  nerves  to  the  superior  and  inferior  maxillae,  the  relation 
between  the  nerves  of  the  temporal  fossa  and  the  internal  maxillary 
vessels,  the  course  and  inosculations  of  the  descendens  noni  and  ex- 
ternal branch  of  the  spinal  accessory,  and  the  position  and  distribu- 
tion of  the  superficial  cervical  plexus. 

The  right  side  of  the  skull,  zygomatic  arch  with  the  temporal  fascia, 
the  ramus  of  the  inferior  maxilla,  and  the  masseter,  platysma,  sterno- 
cleido-mastoid  and  trapezius  muscles  are  removed  ;  the  muscles  to- 
gether with  the  vessels  and  nerves  of  the  face  are  in  part  cut  away, 
and  the  malar  and  dental  canals  are  opened  to  view. 

Hence,  the  dura  mater  and  middle  meningeal  artery,  the  mucous 
membrane  of  the  antrum  of  Highmore,  the  fangs  of  the  teeth,  and 
the  muscles,  vessels,  and  nerves  of  the  temporal  fossa  and  of  the  neck 
situated  under  the  parts  removed  are  seen. 

A. — Skin,  divided  in  the  median  line  from  the  nose  and  glabella  to 
the  neck. 

B. — Frontal  bone.     a.   Coronal  suture,     b.  Right  frontal  sinus. 

C. — Parietal  bone.  c.  Lambdoid  suture,  d.  The  lower  part  of  the 
right  parietal  bone.  e.  Its  anterior  inferior  angle,  f.  Men- 
ingeal canal  in  the  anterior  inferior  angle  divided  transversely. 
g.  Meningeal  grooves. 

D. — Tabular  portion  of  the  occipital  bone. 

E. — Temporal  bone.  h.  Glenoid  fossa,  i.  Eminentia  articularis. 
1c.  Root  of  the  zygomatic  process  divided. 

F. — The  malar  bone,  partly  removed,  to  show  the  malar  foramina. 

G. — Superior  maxillary  bone.  I.  Infraorbital  foramen,  m.  Mucous 
membrane  of  the  antrum  of  Highmore.  n.  Alveoli  and 
fangs  of  the  teeth. 

H. — Inferior   maxillary  bone.     o.   Angle  of  the    inferior    maxillary. 


XXXV111  DESCRIPTION    OF    TUE    PLATES. 

p.  Dental  foramen,  q.  Inferior  dental  canal,  r.  Mental 
foramen,     s.  Alveoli  and  fangs  of  the  teeth. 

I. — The  incisor,  K,  canine,  L,  bicuspid,  and  M,  molar  teeth. 

N. — Hyoid  bone. 

O. — Occipital  portion  of  the  occipito-frontalis  muscle.  P.  Retrahens 
aurem  muscle. 

Q. — Temporal  muscle,     t.  Its  superficial,  and  u,  deep  portions. 

R. — The  external,  and  S,  internal  pterygoid  muscles. 

T. — Posterior  part  of  the  buccinator  muscle.  IT.  Mucous  membrane 
of  the  gums. 

V. — Mylo-hyoid  muscle. 

A. — Insertion  of  the  sterno-cleido-mastoid  muscle. 

E. — Splenius  capitis  muscle,  of  which  a  small  part  is  removed,  to 
show  the  course  of  the  occipital  artery,  z.  Splenius  colli 
muscle.  H.  Upper  part  of  the  trachelo-mastoid  muscle,  seen 
beneath  the  splenius  capitis.  &.  Levator  anguli  scapulae 
muscle.  I.  Upper  part  of  the  biventer  cervicis  muscle.  K. 
Scalenus  medius,  and  A,  scalenus  anticus  muscles.  M.  Ex- 
ternal margin  of  the  rectus  capitis  anticus  major  muscle. 

N  — The  thyroid  gland. 

H. — The  pinna,  turned  forward  to  show  the  distribution  of  the  auricular 
nerves. 

O. — Common  carotid. 

n. — Superior  thyroid  artery,  y.  Superior  laryngeal  artery,  z.  Thy- 
roid branches,     a.  Muscular  branch. 

p. — Lingual  artery,  arising  by  a  common  trunk  with  the  facial. 

2. — Facial  artery.  8.  Submental  artery,  y.  Trunk  of  the  facial, 
divided  transversely. 

T. — External  carotid,  passing  between  the  inferior  maxillary  bone 
and  temporal  vein. 

T. — Occipital  artery.  3".  Arteria  princeps  cervicis.  s  Terminal 
branch. 

*. — Posterior  auricular  artery.  £.  Auricular  branches,  n.  Occipital 
branch,  divided  transversely. 

X. — Internal  maxillary  artery.  &.  Inferior  dental  artery,  i.  Menin- 
geal branches  of  the  middle  meningeal  artery.  Its  anterior 
larger  branch  passes  through  a  canal  in  the  anterior  infe- 
rior angle  of  the  parietal  bone.  x.  Masseteric  artery  divided. 
A.    Posterior   deep    temporal    artery,      /w.    Buccal    artery. 


DESCRIPTION    OF    THE    PLATES.  xxxi.X 

v.  Anterior  deep  temporal  artery.     £.  Posterior  dental  artery. 

o.   Infraorbital  artery. 

Y. — Temporal  artery.  Tlie  divided  branches  of  the  transverse  facial 
artery  are  seen  amongst  the  internal  maxillary  veins  (t). 
it.  Middle  temporal  artery,  which  divides  into  two  branches, 
ascending  (p)  and  transverse  (a-). 

a. — Internal  carotid. 

AA. — Deep  temporal  plexus  of  veins. 

Iil5. — Temporal  vein  composed  of  two  trunk?  which  intercommuni- 
cate. The  superficial  trunk  joins  the  facial  vein  and  the 
deep  trunk  empties  into  the  internal  jugular  vein. 

CC. — Pterygoid  plexus,  -r.  Internal  maxillary  vein.  u.  Deep  facial 
vein  divided. 

DD. — Facial  vein,  divided  near  the  inferior  maxillary  bone. 

EE. — Common  trunk  of  the  facial  veins.  <$>.  Superior  thyroid  vein. 
FF. — Internal  jugular  veiu.     CJG. — Occipital  vein. 

HH. — External  surface  of  the  dura  mater. 

(V.) — Trifacial  nerve. 

iSecond  division.  1.  Subcutaneous  make  nerve.  2.  Its 
temporal,  and  3,  zygomatic  branches.  4.  Infraorbital  nerve. 
5.  Posterior  dental  nerves,  (i.  Buccal  branch.  7.  Dental 
branches.  8.  Branches  to  the  gums.  9.  Inosculation  of 
the  anterior  and  posterior  dental  nerves.  10.  Middle  dental 
nerve.  11.  Anterior  dental  nerve.  12.  Dental  branches, 
and  13,  branches  to  the  gums.     14.  Branch  to  the  nose. 

Third  division.  15.  Buccal  nerve.  16.  Its  posterior  buc- 
cal branches,  and  17,  anterior  buccal  branch  divided.  lv. 
Anterior  deep  temporal  nerve.  19.  Posterior  deep  temporal 
nerve.  20.  Masseteric  nerve  divided.  21.  Internal,  and 
22,  external  roots  of  the  aurieulo-temporal  nerve.  23.  Its 
trunk.  24.  Branch  of  the  auricular  joining  the  facial.  J.". 
Anterior  auricular  nerve  divided.  26.  Superficial  temporal 
nerve.  27.  Lingual  nerve.  28.  Inferior  dental  nerve.  29. 
Mylo-hyoid  nerve.  30.  Its  muscular  branches.  31.  Dental 
branch.  32.  Posterior  inferior,  and  33,  anterior  inferior 
dental  nerve.  34.  Branches  to  the  mouth,  35,  to  the  teeth, 
and  36,  to  the  gums.     37.  Mental  branch  divided. 

(VII.) — Facial  nerve.  38.  Posterior  auricular  nerve.  39.  Branches 
to  the  retrahens  aarem  muscle.  40.  Branch  to  the  occipital 
portion  of  the  occipitofrontal  muscle.     41.  Cervico-facial 


xl  DESCRIPTION    OP    THE    PLATES. 

division  of  the  facial  nerve.  42.  Temporo-facial  division  of 
the  facial  nerve,  inosculating  with  the  auriculo-temporal 
nerve. 

(XI.) — Spinal  accessory  nerve.  43.  External  division.  44.  Branches 
to  the  sterno-cleido-mastoid  muscle.  45.  Branches  to  the 
trapezius  muscle.  46.  Branch  inosculating  with  the  third 
cervical  nerve. 

(XII.) — Hypoglossal  nerve.  47.  Descendens  noni  branch.  48.  De- 
scendens  noni  branches,  uniting  with  branches  of  the  third 
and  fourth  cervical  nerves.  49.  Ansa  hypoglossi,  sometimes 
on  the  jugular  vein  and  sometimes  between  it  and  the  com- 
mon carotid  artery.  50.  Branches  to  the  sterno-hyoid,  omo- 
hyoid, and  sterno-thyroid  muscles.  51.  Curve  of  the  hypo- 
glossal nerve.  52.  Branch  to  the  thyro-hyoid  muscle.  53. 
Lingual  branch. 

(XIII.) — Second  cervical  nerve.  54.  Occipitalis  major  nerve,  piercing 
the  biventer  cervicis  muscle  and  ascending  to  the  occiput. 
55.  Descending  inosculating  branch  of  the  anterior  division 
of  the  second  cervical  nerve. 

(XV.) — Third  cervical  nerve.  56.  Anterior  division.  57.  Branch  to 
rectus  capitis  anticus  major  muscle.  58.  Branches  of  com- 
munication with  the  fourth  cervical,  59,  the  spinal  accessory, 
and  60,  the  descendens  noni  nerves.  61.  The  occipitalis 
minor  nerve,  divided  into  two  branches,  of  which  the  ante- 
rior lesser  one,  (62),  is  cut  out  ;  the  posterior  greater  one, 
(63),  sends  its  filaments  to  the  anterior  region  of  the  occiput. 

64.  Auricularis  magnus  and  superficialis  colli  nerves  divided. 

65.  Distribution  of  the  auricularis  magnus  to  the  posterior 
surface  of  the  pinna.     66.   Branch  to  the  splenitis  capitis  et 

colli  muscle. 

(XVI.) — Fourth  cervical  nerve.  67.  Anterior  division.  68.  Branch 
to  the  rectus  capitis  anticus  major  muscle.  69.  Ascending, 
and  70,  descending  inosculating  branches.  71.  Branches  to 
the  levator  anguli  scapulae  and  splenitis  colli  muscles.  72. 
Supraclavicular  branches. 

(XVII.) — Fifth  cervical  nerve.     73.  Its  anterior  division. 

(XVIII.) — Trunk  of  the  sympathetic  in  the  neck,  (74). 


PLATE    VIII. 


'P\l> 


DESCRIPTION    OF    THE    PLATES.  xli 


PLATE    VIII. 

DISTRIBUTION  OF  THE  NERVES  OF  THE  PACE  AND  NECK 
UNDER  THE  8UBCUTANEOUS  MUSCLES  OF  THE  FACE, 
THE  PLATYSMA,  AND  THE  TRAPEZIUS. 

The  right  side  of  the  head,  with  the  exit  and  distribution  of  the 
first,  second,  and  third  divisions  of  the  fifth  nerve  in  the  face,  the 
course  and  ramifications  of  the  facial  nerve  under  the  subcutaneous 
muscles  of  the  face,  and  the  course  and  distribution  of  the  superficial 
cervical  nerves  under  the  platysma  and  trapezius  muscles  are  seen. 

The  skin  and  adipose  tissue  of  the  right  Bide,  occipito-frontalis 
aponeurosis,  the  pericranium  and  external  table  of  the  skull  are  re- 
moved by  layers,  the  diploe'  being  removed  to  the  vitreous  table  on 
the  anterior  portion  of  the  parietal  bone  ;  the  parotid  gland  is  taken 
out  piece-meal,  the  muscles  of  the  face  are  partly,  and  the  platysma 
and  trapezius  wholly  removed. 

Therefore  we  see,  firstly,  the  layers  of  the  scalp  and  skull  :  sec- 
ondly, the  muscles,  vessels,  and  nerves  found  under  the  parotid 
gland  and  subcutaneous  muscles  of  the  face  and  neck,  then  the  exit 
of  the  nerves  from  the  cranium  into  the  face,  and  finally  the  distri- 
bution of  the  nerves  under  the  subcutaneous  muscli 

A. — Section  of  the  skin  and  adipose  tissue  in  the  median  line. 

B. — Aponeurosis  of  the  occipito-frontalis  muscle,  likewise  divided. 

C. — Pericranium. 

I>. — The  skull.  a.  The  outer  table,  b.  Diploe  of  the  frontal  bone. 
c.  Frontal  diploic  veins.  <l.  Diploe  of  the  posterior  part  of 
the  parietal  and  superior  part  of  the  occipital  bones,  e.  Pa- 
rietal diploic  veins,  f.  Coronal  suture.  </.  Vitreous  table 
of  the  anterior  portion  of  the  parietal  bone,  the  inner  sur- 
face of  which  is  traversed  by  arterial  grooves. 

E. — Temporal  fascia,  covering  the  temporal  muscle.  h.  The  inner, 
and  i,  outer  layers  of  the  temporal  fascia.  The  outer  layer 
is  removed  at  the  position  of  the  middle  temporal  vein,  so 
that  its  course  may  be  seen.  /.  Semilunar  opening  in  the 
superficial  layer,  through  which  the  middle  temporal  vein 
passes.     /.  Opening  in  the  deep  layer  for  the  passage  of  the 


xlii  DESCRIPTION    OF    THE    PLATES. 

deep  temporal  vein.  m.  Malar  foramina  in  the  temporal 
fascia. 

F.— Eyelids. 

O. — Malar  bone.     n.   External  malar  foramina,     o.  Zygomatic  arch. 

H. — Superior  maxillary  bone.     j>.   Infraorbital  foramen. 

I. — Nasal  bone. 

K. — Nasal  cartilages  :  q,  superior  lateral,  r,  lower  lateral,  and  s, 
sesamoid. 

L. — Inferior  maxillary  bone.  t.  Mental  foramen,  u.  Ramus  of  the 
inferior  maxillary  bone. 

M. — Hyoid  bone 

N. — The  pinna. 

O. — Origin  of  the  zygomaticus  major  muscle.  P. — Levator  anguli 
oris  muscle.  Q. — Buccinator  muscle.  R. — Depressor  an- 
guli oris,  and  S,  depressor  labii  inferioris  muscles  divided 
near  their  origins.     T. — Levator  labii  inferioris  muscle. 

U. — Temporal  muscle,  divided  transversely.  V. — Masseter  muscle. 
v.  Its  deep,  and  w,  superficial  portions. 

AV. — Sterno-cleido-mastoid  muscle. 

X. — Trapezius  muscle,  divided  near  its  origin.  Y.  —  Splenitis  capitis 
et  colli  muscle.  Z.  —  Levator  anguli  scapula?  muscle. 
A. — Biventer  cervicis  muscle. 

B. — Sterno-hyoid  muscle,  r. —  Superior  belly  of  the  omo-hyoid 
muscle.  A. — Superior  extremity  of  the  sterno-thyroid 
muscle.     E. — Thyro-hyoid  muscle. 

z. — Insertion  of  the  stylo-hyoid  muscle.  H. — Digastric  muscle. 
x.  Its  anterior  belly,  y.  Central  tendon.  z.  Suprahyoid 
aponeurosis. 

©. — Superior  thyroid  artery. 

I. — Facial  artery,  a.  Muscular  branch.  B.  Mental  branches,  y. 
Buccal  branches.  i.  Anastomosis  of  a  buccal  branch  with 
the  transverse  facial  artery,  e.  Inferior,  and  £,  superior 
coronary  arteries.  ».  Anastomosis  with  the  infraorbital 
artery.  &.  Artery  of  the  nasal  septum.  «.  Lateralis  nasi 
artery,    x.  Branch  anastomosing  with  the  ophthalmic  artery. 

K. — Ophthalmic  artery,  x.  Frontal  artery,  fx.  Nasal  artery,  v.  Su- 
praorbital artery. 

A. — Temporal  artery,  partly  covered  by  the  trunk  of  the  temporal 
vein.     £.  Transverse  facial  artery. 


DESCRIPTION    OF    THE    PLATES.  xllll 

M. — Internal  maxillary  artery,  o.  Buccal  artery,  n.  Mental  artery. 
p.  Infraorbital  artery,  a.  Superficial  perforating  branch  of 
the  anterior  deep  temporal  artery. 

N. — Posterior  auricular  artery. 

5. — Occipital  artery. 

O. — Facial  vein.  A  great  portion  of  the  trunk  of  this  vein  is  removed, 
so  that  the  exit  of  the  infraorbital  nerve  may  be  seen. 
t.  Frontal  vein.  0.  Supraorbital  vein.  <p.  Dorsalis  nasi 
vein.  %.  Anterior  extremity  of  the  ophthalmic  vein.  ¥.  Lat- 
eralis nasi  vein.  <u.  Deep  facial  vein.  aa.  Infralabial  vein. 
bb.  Submental  vein. 

n. — Temporal  vein,  which  is  sometimes  double,  cc.  Superficial  tem- 
poral vein.  (Id.  Middle  temporal  vein,  which  anastomoses 
with  the  supraorbital,  (ee),  subcutaneous  temporal,  (Jj),  and 
deep  temporal,  (<jy),  veins.  /<//.  Auricular  veins.  ii.  Mus- 
cular veins,     /•/.-.  Internal  maxillary  vein. 

P. — Trunk  of  the  external  jugular  vein. 

Z. —  Superficial  cervical  vein.  //.  Occipital  vein.  mm.  Anastomosing 
branch  with  the  deep  cervical  plexus.  int.  Cervical 
branches. 

T.  —  Submaxillary  gland. 

(V.) — Trifacial  nerve. 

First  division.  1.  Frontal  branches  of  the  supraorbital  nerve,  at 
times  passing  over  and  at  times  under  the  supraorbital  vein. 
Many  branches  issue  between  the  frontal  notch  and  the 
superior  palpebral  aponeurosis,  only  one  issues  through  the 
frontal  foramen  from  the  orbit.  2.  Superior  palpebral 
branch  of  the  frontal  nerve  coming  through  a  foramen  of  the 
aponeurosis,  and  3,  the  supratrochlear  nerve  coining  through 
another.  4.  Frontal,  and  5,  superior  palpebral  brandies  of 
the  supratrochlear  nerve,  b".  Infratrochlear  nerve.  7.  Ex- 
ternal branch  of  the  nasal  nerve. 
Second  division.  8.  Subcutaneous  branches  of  the  tern  poro- in  alar 
nerve,  coming  through  openings  in  the  temporal  fascia. 
9.  Their  junction  with  the  facial  nerve.  10.  Zygomatic 
branches  of  the  subcutaneous  malse  nerve  divided.  11.  In- 
fraorbital nerve.  12.  Inferior  palpebral  branches.  13.  Junc- 
tion with  the  facial  nerve.  14.  Superior,  and  15,  inferior 
lateral  nasal  branches,     lb'.  Internal,  and  17,  external  supe- 


xliv  DESCRIPTION    OF    THE    PLATES. 

rior  labial  branches.  18.  Buccal  branches.  19.  Junction 
with  the  facial  nerve. 
Third  division.  20.  Mental  nerve.  21.  Mental  branches.  22.  In- 
ternal, and  23,  external  inferior  labial  branches.  24.  Buccal 
branches.  25.  Junction  with  the  facial  nerve.  26.  The 
anterior  buccal  branches  of  the  buccal  nerve.  27.  Their 
junction  with  the  facial  nerve.  28.  Branches  of  the  auriculo- 
temporal, communicating  with  the  facial  nerve.  29.  Super- 
ficial temporal  branch  of  the  auriculo-temporal  nerve. 

VII. — Trunk  of  the  facial,  seen  in  the  infraauricular  fossa.  30. 
Temporo-facial  division  of  the  facial  nerve.  31.  Temporal, 
32,  malar,  and  33,  superior  buccal  branches.  34.  Cer- 
vicofacial division  of  the  facial  nerve.  35.  Inferior  buccal 
branches.  36.  Supramaxillary  branch.  37.  Inframaxillary 
branch.  38.  Its  inosculation  with  the  superficialis  colli.  39. 
Intercommunication  of  the  branches  of  the  facial,  forming 
the  pes  anserinus.  Many  branches  of  the  facial  nerve  are 
cut  through  near  the  muscles  of  the  face,  which  are  re- 
moved. 

(XI.) — Spinal  accessory  nerve.  40.  Its  external  division,  going  to 
the  trapezius  muscle. 

(XIV.) — Seco'nd  cervical  nerve.  41.  Occipitalis  major  nerve,  piercing 
the  biventer  cervicis  muscle.  42.  Cervical  cutaneous  branch 
divided.     43.  Occipital  branches. 

(XV.) — Third  cervical  nerve.  44.  Occipitalis  minor.  45.  Auricular  is 
magnus  nerve.  46.  Its  facial  branch  divided,  and  47,  its 
auricular  branch.  48.  The  middle,  and  49,  inferior  branches 
of  the  superficialis  colli.     50.  Cutaneous  branches  divided. 

51.  Branches  going  to  the  levator  anguli  scapulae  muscle. 

52.  Junction  with  the  fourth  cervical  nerve. 

(XVI.) — Fourth  cervical  nerve.  53.  Supraclavicular  branches.  54 
Phrenic  nerve. 


PLATE    IX. 


DESCRIPTION    OF    THE    PLATES.  xlv 


PLATE    IX. 

COURSE  OF  THE  SUBCUTANEOUS  CRANIAL  NERVES.  THE 
SUPERFICIAL  DISTRIBUTION  OF  THE  FACIAL,  FIRST, 
SECOND,  AND  THIRD  DIVISIONS  OF  THE  TRIFACIAL,  AND 
THE  SUBCUTANEOUS  RAMIFICATIONS  OF  THE  SECOND. 
THIRD,  AND  FOURTH  CERVICAL  NERVES  ON  THE  BIGHT 
SIDE  OF  THE  HEAD. 

The  skin  of  the  right  side  of  the  head  and  neck  is  removed,  bring- 
ing the  subjacent  parts  into  view. 

Therefore  the  parotid  gland,  Stenson's  duct,  and  the  subcutaneous 
muscles,  vessels,  and  nerves  of  the  head,  face,  and  neck  may  he 
.seen. 

A. — Skin  and  adipose  tissue  divided  in  the  median  line. 

15. — Pinna,  with  the  helix  turned  forward  to  show  the  retrahens 
aurem  muscle  and  posterior  auricular  nerve. 

C. — Epicranial  muscle,  a.  Its  occipital  portion,  b,  aponeurosis,  and 
c,  frontal  portion. 

I). — Attolens  aurem  muscle. 

E. — Retrahens  aurem  muscle. 

F. — Orbicularis  palpebrarum  muscle,  d.  Its  orbital,  and  e,  palpe- 
bral  portions. 

G. — Pyraniidalis  nasi  muscle.  H.  Compressor  nasi  muscle.  I. 
Levator  labii  superioris  alaeque  nasi  muscle.  /.  Its  nasal, 
and  (j,  lahial  portions. 

K. — Levator  labii  superioris  proprius,  L,  levator  anguli  oris,  M, 
zygomaticns  major,  N,  zygomaticus  minor,  O,  buccinator, 
P,  risorius,  Q,  depressor  anguli  oris,  K,  depressor  labii  in- 
ferioi  is.  S,  orbicularis  oris,  and  T,  levator  labii  inferioris 
muscles. 

U. — Masseter  muscle,     h.     Its  superficial,  and  i,  deep  portions. 

V. — Platysma  muscle.  W.  Sterno-cleido-mastoid  muscle,  k.  Its 
superior  tendinous  extremity. 

X. — Trapezius,  and  Y,  splenius  capitis  et  colli  muscles.  Z.  Leva- 
tor anguli  scapulae  muscle. 

A. — Parotid  gland.     /.  Stenson's  duct.     in.  Accessory  parotid  gland. 


xlvi  DESCRIPTION    OF    THE    PLATES. 

j?  — Facial  artery,  n.  Masseteric  branch  anastomosing  with  a  branch 
of  the  transverse  facial  artery.  o.  Buccal  branch,  also 
anastomosing  with  a  branch  of  the  transverse  facial  artery. 
p.  Artery  of  the  nasal  septum  g.  Lateralis  nasi  artery. 
r.  Dorsalis  nasi  artery,  s.  Angular  artery,  t.  Anastomosis 
with  the  ophthalmic  artery. 

r. — Temporal  artery,  u.  Superior,  and  v,  inferior  branches  of  the 
transverse  facial  artery.  w.  Zygomaticoorbital  artery. 
x.  Anastomosing  branch  with  the  transverse  facial  artery. 
y.  Anterior,  and  z,  posterior  superficial  temporal  arteries. 
«.  Anastomoses  with  the  supraorbital,  and  8>  occipital 
arteries. 

A.  Posterior  auricular  artery,  y.  Auricular  branches,  i.  Occipital 
branch. 

E.  Occipital  artery,     e.  Terminal  occipital  branch. 

Z.  Ophthalmic  artery.  £.  Supraorbital  artery,  passing  through  the 
frontal  muscle  and  then  ascending  upon  it.  n.  Dorsalis  nasi 
artery.     S.  Branch  anastomosing  with  the  facial  artery. 

H.  Facial  vein.  i.  Frontal  vein.  x.  Dorsalis  nasi  vein.  x.  Branch 
of  the  supraorbital  vein,  perforating  the  orbicularis  palpe- 
brarum muscle  and  anastomosing  with  the  facial  vein. 

0  Temporal  vein.  /t*.  Superficial  temporal  vein.  v.  Its  anterior, 
and  £,  posterior  branches,  o.  Anastomoses  with  the  frontal, 
ir,  supraorbital,  and  f>,  occipital  veins,  a-.  Middle  temporal 
vein.  t.  The  trunk  of  the  temporal  vein  is  here  double,  but 
usually  only  one  trunk  is  found. 

I.  External  jugular  vein,  covered  by  the  platysma  muscle. 

K.  Superficial  cervical  vein.  v.  Occipital  vein.  <f>.  Anastomosing 
branch  with  the  deep  cervical  plexus.   £.  Cervical  branches. 

(V.) — Trifacial  nerve. 

First  division.     1.  Frontal  branches  of  the  frontal  nerve,  passing 

through  the  fibres  of  the  frontal  muscle,  then  going  to  the  vertex 

subcutaneously.     2.  Frontal  branches  of  the  supratrochlear  nerve. 
Second  division.      3.  Inferior  palpebral  branch  of   the  infraorbital 

nerve.     4.  Laterales  nasi  branches  of  the  infraorbital  nerve. 

Third  division.      5.  Anterior  auricular   branch,   and    6,    temporal 

branches  of  the    auriculotemporal   nerve.      7.  The   anterior  buccal 

branches  of  the  buccal  nerve.     8.  Branches  of  the  buccal  joining  the 

facial  nerve. 


DESCRIPTION    OF    THE    PLATES.  xlvii 

(VII.) — Facial  nerve.  9.  Posterior  auricular  nerve.  10.  Temporal, 
11,  malar,  12,  superior  buccal,  and  13,  inferior  buccal 
branches  14.  Supramaxillary,  and  15,  inframaxillary 
branches.  16.  Branch  piercing  the  platysma  muscle.  17. 
Inosculation  with  the  middle  Buperficialis  colli  nerve.  18. 
Intercommunicating  branches  of  the  facial  nerve 

(XL) — Spinal  accessory  nerve.  19  Its  external  division,  going  to  the 
trapezius  muscle. 

(XIV.  — Second  cervical  nerve.  20.  Occipitalis  major  nerve,  piercing 
the  bi venter  cervicis  and  part  of  the  trapezius  muscles, 
''ranches  of  this  nerve  accompany  the  occipital  artery  and 
vein  to  the  vertex. 

(XV.) — Third  cervical  nerve.  21.  Occipitalis  minor,  one  branch  of 
which  pierces  the  border  of  the  trapezius  muscle  and  ascends 
to  the  anterior  part  of  the  occiput  ;  another  branch  passes 
amongst  the  branches  of  the  superficial  cervical  vein,  joins 
the  occipitalis  major  nerve  and  goes  to  the  vertex.  22.  An- 
terior cervical  cutaneous  branches.  23.  Auricularis  magnus 
nerve.  24.  Its  auricular  branches.  25.  Facial  branch  of 
the  auricularis  magnus.  26.  Facial  cutaneous  branches 
divided.  27.  Cutaneous  branches  piercing  the  platysma 
muscle.  28.  Superficialis  colli  nerves  piercing  the  platysma 
muscle.     29.  Branches  to  the  levator  anguli  scapuhe  muscle. 

(XVI.) — Fourth  cervical  nerve.     30.  Its  anterior  division. 


ESSENTIALS  OF  HUMAN  PHYSIOLOGY. 


What  is  physiology? 

Physiology  is  the  study  of  vital  phenomena  which  are  always 
present  in  living  things  he  they  animal  or  vegetable.  As  a  con- 
sequence of  this  we  divide  physiology  into  two  subdivisions,  known 
as  animal  physiology  and  vegetable  physiology,  but  it  should  be 
remembered  that  the  line  of  demarcation  between  animals  and 
vegetables  in  the  lower  forms  of  life  is  very  ill-defined.  The  word 
physiology  is  derived  from  the  Greek  word  avoir,  nature,  and 
a  discourse,  and  in  its  original  meaning  was  applied  to  the  study 
of  natural  history  in  general.  Physiology  is  really  synonymous 
with  the  term  biology,  since  it  is  necessary  for  the  study  of  either 
one  that  vital  properties  be  present  in  the  thing  studied.  The  term 
biology,  however,  has  a  wider  scope  with  certain  persons,  as  under 
some  circumstances  it  is  divided  up  into  morphology,  which  treats 
of  the  forms  and  structure  of  living  bodies,  while  physiology  at- 
tempts to  explain  the  modes  of  activity  exhibited  by  them  during 
their  lifetime.  In  other  words,  morphology  stands  in  the  same 
position  in  reference  to  physiology  as  does  anatomy.  The  term 
vital  phenomena  is  applied  to  the  changes  which  constantly  go  on 
in  all  living  bodies,  the  primary  causes  of  which  are  not  at  all 
understood ;  in  other  words,  while  we  note  the  ultimate  object  of 
each  function  we  can  give  no  cause  for  the  setting  in  motion  of 
that  function. 

What  is  the  chemical  basis  of  the  body? 

Of  the  sixty-nine  elements  known  to  chemists,  a  very  small 
number,  comparatively  speaking,  are  found  in  any  quantity  in 
living  animal  matter,  although  traces  of  them  are  frequently 
present.  Oxygen,  carbon,  hydrogen,  and  nitrogen  are  present  in 
very  large  proportions  in  every  tissue,  and  together  make  up  about 
97  per  cent,  of  the  whole  body,  while  the  sulphur,  phosphorus, 
chlorine,  fluorine,  silica,  potassium,  sodium,  magnesium,  calcium, 

2 


18        ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

and  iron  are  indispensable  to  the  economy,  but  are  widely  distrib- 
uted and  occur  in  much  smaller  quantities.  Since  to  investigate 
the  chemical  composition  of  a  tissue  must  require  analysis,  the 
composition  of  the  tissues  during  life  is,  strictly  speaking,  un- 
known, since  by  the  very  analysis  death  is  produced.  An  im- 
portant point  to  be  remembered  is  that  all  animal  bodies,  be  they 
simple  or  complex,  are  made  up  of  protoplasm  more  or  less  differ- 
entiated according  to  the  function  which  it  is  to  fulfil. 

What  two  great  groups  of  substances  make  up  the  body  ? 

Physiological  chemistry  teaches  us  that  we  have  in  the  body  two 
sets  or  groups  of  substances  known  as  nitrogenous  and  non-nitro- 
genous. The  nitrogenous  perform  the  most  important  functions, 
and,  indeed,  form  all  the  active  portions  of  the  organism.  As  the 
simplest  representative  of  these  nitrogenous  bodies  may  be  men- 
tioned protoplasm  itself.  Derived  from  this  and  entering  into  the 
formation  of  it  are  albumens,  serum-albumens,  and,  thirdly,  by 
the  outcome  of  still  further  differentiation  we  have  albuminoids, 
chiefly  represented  by  gelatine.  Last  of  all  are  those  products 
which,  though  nitrogenous,  differ  from  the  others  in  that  they  are 
intermediate  or  effete  products  of  tissue  manufacture  or  waste,  as, 
for  example,  urea,  uric  acid,  kreatin,  and  kreatinin.  The  non- 
nitrogenous  substances  consist  chiefly  of  the  carbohydrates,  which 
contain  hydrogen  and  oxygen  in  the  proportion  found  in  water,  as, 
for  example,  starch  and  sugar.  Then  we  have  substances  contain- 
ing oxygen  in  less  proportion  than  the  above,  namely,  fats.  Salts 
occur  all  through  the  tissue,  as  does  also  water. 

PROTEIDS. 

All  compounds  included  in  the  group  of  proteids  contain  carbon, 
hydrogen,  nitrogen,  oxygen,  and  sulphur. 
They  are  amorphous,  with  variable  solubility  in  water  and  acids, 
usually  soluble  in  alkalies,  almost  insoluble  in  alcohol  and  ether. 
They  are  precipitated  from  their  solutions  by  excess  of  strong 
mineral  acids,  by  acetic  or  hydrochloric  acid,  potassium  ferro- 
cyanide,  and  the  basic  acetate  of  lead,  mercury  bichloride,  tannin, 
and  potassium  carbonate  in  powder. 


CLASSIFICATION    OF    PROTEIDS. 


19 


Soluble  in 
pure  water 


The  following  table,  taken  from  Gaingee's  Physiological  Chem- 
istry, is  of  great  importance,  and  gives  the  points  to  be  remembered 
most  tersely.  This  will  be,  of  necessity,  frequently  referred  to 
later  on. 

Class  1.—  Albumens  are  proteid  liodies  which  are  soluble  in  water,  aud 
which  are  not  precipitated  by  alkaline  carbonates,  by  sodium  chlo- 
ride, or  by  very  diluto  acids.  It"  dried  at  a  temperature  below  40° 
C.  they  become  transparent  and  yellow,  break  with  vitreous  frac- 
ture, and  are  soluble  in  water.  Coagulation  occurs  between  65° 
ami  7::    0. 

1.  Serum-albumen,  not  precipitated  from  its  rotations  by  the 
addition  of  ether. 

2.  Egg-albumen,  precipitated  from  its  solution  by  agitation  with 
ether. 

I  i  ass  2. -Peptones,  proteid  bodies  exceedingly  soluble  in  water.  Solu- 
tions are  not  coagulated  by  heat  when  precipitated  by  sodium  chlo- 
ride, nor  by  acids  or  alkalies  ;  precipitated  by  a  large  excess  of 
absolute  alkali  and  by  tannic  acid  in  the  presence  of  much  caustii 
potash  or  soda.  A  trace  of  a  solution  of  copper  sulphate  producesa 
[  beautiful  rose  color. 

Class  3.—Gl<,buli)is,  proteid  substances  which  are  insoluble  in  pure 
water  but  soluble  in  dilute  solutions  of  NaCl.  These  solutions  are 
coagulated  by  heat  They  are  soluble  in  dilute  hydrochloric  acid, 
being  converted  by  alkalies  into  alkali-albumen. 

1.  Vitellin,  not  precipitated  from  its  solution  when  saturated 

with  common  salt. 
-'.  Myosin,  precipitated  from  its  solution  by  weak  common 
salt.  When  saturated  with  sodium  chloride  it  coagulates 
at  55°  to  00°  C.  Solutions  in  common  salt  are  not  coagu- 
lated by  a  solution  of  fibrin-ferment. 
.?.  Fibrinogen,  soluble  in  weak  solutions  of  NaCl,  precipitated 
from  them  completely  on  the  addition  of  NaCl  when  this 
amounts  to  twelve  or  sixteen  percent.  Solutions  coagulate 
on  the  addition  of  fibrin-ferment  and  at  the  temperature  of 
60°  C. 
4.  Paraglobulin,  soluble  in  weak  solutions  of  NaCl,  and  pre- 
cipitated from  weak  alkalino  solutions  by  the  addition  of  a 
small  quantity  of  NaCl.  A  further  addition  of  this  body 
redissolves  the  precipitate,  which  is  again  precipitated, 
although  not  so  completely  as  before.  When  the  amount 
of  NaCl  in  solution  exceeds  twenty  percent,  paraglobulin 
is  completely  precipitated  when  the  solution  is  saturated 
with  ammonium  sulphate.  Its  solutions  are  not  precipitated 
by  the  addition  of  the  fibrin  ferment  It  coagulates  at 
different  temperatures  according  to  the  amount  of  salts 
present  and  the  mode  of  heating,  but  generally  between 
68°  and  80°  C. 


Insoluble  in 
pure  water, 
but  soluble 
in  weak 
solutions  of 
common  salt 


20         ESSENTIALS    OF     HUMAN     PHYSIOLOGY. 

Class  4. — Derived  albumens,  proteid  bodies  insoluble  in  pure  water  aud  in  solution?  of 
NaCl,  but  readily  soluble  in  dilute  HC1  and  h.  dilute  alkaline  solutions.  Solutions 
are  not  coagulated  by  neat. 

1.  Acid-albumens,  obtained  by  the  action  of  dilute  acids,  especially  HC1,  on 

solutions  of  proteids,  and  by  action  of  strong  acids  upon  solid  proteids. 
They  occur  as  first  products  in  the  action  of  gastric  juice.  NaCl  added  to 
saturation  precipitates  them. 

2.  ('<)  Alkali-albumens,  obtained  by  the  action  of  dilute  alkalies  upon  the  pro- 

teids, possessing  the  properties  of  acid-albumen  with  the  exception  that  in 
the  presence  of  an  alkaline  phosphate  the  solutions  are  not  precipitated  by 
neutralization.  They  occur  as  the  first  products  of  pancreatic  digestion 
(6)  Casein,  the  chief  proteid  constituent  of  milk,  has  the  same  properties  as 
alkali-albumen,  but  when  treated  with  a  strong  solution  of  caustic  potash 
potassium  sulphide  is  formed  ;  with  alkali-albumen  it  is  not  formed. 

Class  5. — Fibrin  is  insoluble  in  water  and  in  weak  solutions  of  NaCl,  and  becomes 
swelled  up  in  cold  hydrochloric  acid  of  one-tenth  per  cent,  solution,  but  does  not 
dissolve  unless  pepsin  is  added  and  heat  is  applied. 

1.  What  tests  have  we  for  proteids? 

The  nitric  acid  test,  which  consists  in  heating  the  liquid  and 
adding  nitric  acid  until  the  reaction  is  strongly  acid,  when  a  pre- 
cipitate occurs.  Remember,  that  this  is  not  an  infallible  test  for  all 
proteids,  as,  for  esample,  the  peptones,  which  will  not  respond  to  it. 

2.  What  is  the  xantho-proteic  reaction? 

Heat  with  concentrated  nitric  acid,  when,  if  a  proteid  be  present, 
a  yellow  tint  appears,  which  becomes  reddish-orange  on  the 
addition  of  alkalies. 

3.  What  is  Millon's  reagent? 

It  is  made  by  dissolving  in  the  cold  one  part  of  mercury  in  its 
weight  of  concentrated  nitric  acid,  the  solution  being  completed 
by  applying  gentle  warmth ;  two  volumes  of  distilled  water  are 
then  added,  and  the  fluid  decanted.  This  test  gives  a  red  color 
with  liquids  containing  proteids,  which  is  more  marked  when  they 
are  heated  to  60°  C.  or  70°  C. 


CARBO-HYDRATES. 

These  include  the  starches  and  sugars. 

What  test  have  we  for  starch  ? 

March,  when  added  to  free  iodine,  strikes  a  blue  color  which  dis- 
appears on  the  application  of  heat,  but  returns  if  the  liquid  be 


THE    BLOOD.  21 

suddenly  cooled.  If  heated  to  the  temperature  of  210°  C.  starch  is 
converted  into  dextrin,  and,  as  we  shall  learn  later,  the  digestive 
fluids  change  starch  into  glucose  or  grape  sugar. 

Sugars  are  substances  having  a  more  or  less  sweet  taste,  usually 
soluble  in  water,  destroyed  by  strong  H2S04,  which  abstracts  water 
from  these  compounds,  and  leaves  only  the  carbon.  The  most 
important  of  this  group  are  glucose,  lactose,  saccharose,  and  gly- 
cogen.    <  )n  fermentation  they  yield  C0.2  and  alcohol. 

What  test  have  we  for  sugars  ? 

Trammer's  (est,  which  depends  upon  the  fact  that  sugar  in  an 
alkaline  solution  acts  as  a  reducing  agent.  To  the  saccharine 
fluid  about  one-fourth  of  its  bulk  of  caustic  potash  or  soda  is  added, 
and  a  dilute  solution  of  copper  sulphate.  A  slight  clouding  occurs 
which  disappears  on  shaking,  but  boiling  strikes  a  brick-red  color. 

Fats  are  widely  distributed  in  plants  and  in  animals.  They 
contain  very  little  oxygen,  and  are  soluble  in  ether,  benzole,  chloro- 
form, and  in  boiling  alcohol.  When  fats  are  boiled  with  solutions 
of  the  alkaline  hydrates  or  carbonates  they  undergo  saponification, 
and  are  decomposed  into  glycerin  and  fatty  acids.  The  latter 
immediately  combine  with  the  alkali  and  form  soap. 

Fats  also  undergo  emulsification,  in  which  process  they  are 
broken  up  into  a  condition  of  extremely  fine  subdivision. 


THE    BLOOD. 

What  is  the  function  of  the  blood  ? 

In  all  animals,  except  those  which  form  the  lowest  class,  a  liquid 
medium  corresponding,  in  function  at  least,  to  the  blood  of  man, 
circulates.  It  serves  in  the  distribution  of  nutritious  materials  to 
the  various  parts  of  the  system  and,  equally  important,  it  collects 
those  substances  which  have  resulted  from  the  changes  which  are 
constantly  going  on  in  the  tissues  and  bears  them  to  those  organs 
whose  function  it  is  to  discharge  them  from  the  body.  Quite  aa 
important  is  the  constant  intercourse  which  it  keeps  up  between 
the  tissues  and  the  air,  supplying  them  with  oxygen. 


22         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  is  the  color  of  the  blood  in  the  different  portions  of 
the  circulatory  system  ? 
The  color  of  the  blood  as  it  occurs  in  the  systemic  arteries  is  of 
a  bright  scarlet-red,  while  in  the  corresponding  veins  it  is  of  a 
dark  bluish  color.  In  the  pulmonary  artery  it  is  dark  blue,  in 
the  pulmonary  veins  scarlet. 

What  is  the  cause  of  this  variation  ? 

The  cause  of  this  variation  is  due  to  the  oxygen  of  the  air,  which, 
entering  into  a  chemical  combination  with  the  haemoglobin  of  the 
red  blood  corpuscles,  produces  oxyhemoglobin,  which  gives  up 
some  of  its  oxygen  to  the  tissues  of  the  body  as  it  passes  through 
the  capillaries,  and  returns  in  the  veins  partly  decomposed  into  re- 
duced haemoglobin,  which  gives  to  the  venous  blood  its  dark  hue. 

Is  the  entire  amount  of  oxyhaemoglobin  reduced  in  venous 
blood  ? 

No.  The  reduction  of  haemoglobin  amounts  to  only  about  five 
per  cent. 

Are  the  red  blood  corpuscles  red  or  yellow  ? 

They  are  red,  for  their  coloring  matter,  haemoglobin,  is  red  when 
isolated  and  crystallized. 

The  color  of  the  red  corpuscles  when  seen  singly  is  yellowish-red. 

The  difference  in  color  between  those  seen  en  masse  and  those 
seen  singly  is  due  to  the  refraction  of  light. 

What  is  the  reaction  of  the  blood  ? 

The  reaction  is  alkaline,  owing  to  the  presence  of  sodium  carbo- 
nate and  disodic  phosphate,  Na^HPO^ 

Does  it  always  retain  its  alkalinity  ? 

Always  during  life,  but  after  blood  is  shed  its  alkalinity  rapidlj 
diminishes,  and  the  greater  the  alkalinity  of  the  blood  is,  the  more 
rapidly  this  change  occurs.  Finally,  the  reaction  becomes 
strongly  acid,  this  change  coming  at  about  the  time  of  coagula- 
tion. 

What  is  the  odor  of  the  blood  ? 

The  odor  which  the  blood  possesses  differs  in  the  various 
animals,  and  in  some  animals  is  very  characteristic.  This  odor 
depends  upon  the  presence  of  volatile  fatty  acids. 


THE    BLOOD.  23 

What  is  the  taste  ? 

It  is  saline  in  taste,  which  is  dependent  upon  the  salts  contained 
in  it. 

What  is  the  specific  gravity  of  the  blood  ? 

The  specific  gravity  is  1055,  the  extreme  limits  being  from 
1045  to  1075.  The  specific  gravity  of  the  blood  corpuscles  alone 
is  1105,  that  of  the  plasma  1027.  As  a  consequence  of  this,  blood 
corpuscles  tend  to  sink  to  the  bottom  of  the  receptacle  into  which 
the  blood  is  drawn. 

What  is  the  temperature  of  the  blood  ? 

It  varies  from  98°  F.  at  the  surface  of  the  body  to  107°  in  the 
hepatic  vein. 

Of  what  does  the  blood  consist  ? 

Blood,  when  flowing  in  a  normal  condition  through  the  blood- 
vessels, consists  of  an  almost  colorless  fluid,  the  plasma,  in  which 
are  suspended  small  solid  bodies,  known  as  red  and  white  blood 
corpuscles  and  blood-plates.  The  liquid  portion  of  the  blood  (the 
blood  plasma  or  liquor  sanguinis)  is  of  a  pale  straw  color  when 
free  from  blood  corpuscles  or  other  coloring  matter,  and  is  the 
liquid  which  keeps  the  corpuscles  afloat.  The  blood  plasma  is  not 
identical  with  the  serum  of  the  blood,  since  radical  changes  take 
place  in  its  composition  during  coagulation,  and  the  serum  results 
after  the  clot  is  formed.  Serum  will  not  of  itself  form  a  clot, 
plasma  will ;  in  other  words,  one  of  the  differences  between  liquor 
sanguinis,  or  plasma,  and  serum,  is  that  the  first  contains  fibrino- 
gen, while  the  second  does  not. 

Is  there  any  variation  in  the  character  of  the  blood  in 
different  parts  of  the  circulatory  system  ? 
The  arterial  blood  contains  more  oxygen  and  less  C02,  and  is 
more  coagulable.  The  blood  of  the  portal  vein  varies  with  the 
stages  of  digestion,  during  which  time  it  is  richer  in  water,  albu- 
minous matters,  and  sugars,  with  a  diminished  number  of  cor- 
puscles. In  the  hepatic  vein  the  sugar  is  increased,  but  the 
albumin  and  fibrinogen  diminished. 


24  ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  are  the  two  varieties  of  blood  corpuscles  ? 

Red  and  white. 

What  others  have  we? 

Very  small  ones,  known  as  microcytes,  and  the  so-called  blood- 
plates. 

What  is  the  function  of  these  microcytes  ? 

Most  physiologists  believe  them  to  be  young  red  blood  corpuscles, 
others  that  they  are  worn-out  red  blood  corpuscles. 

What  is  the  function  of  the  blood-plates  ? 

It  is  not  known,  but  they  are  found  in  large  numbers  in  thrombi, 
and  possibly  take  part  in  the  process  of  coagulation  by  helping  to 
form  fibrin-ferment.     They  do  not  become  red  corpuscles. 

Describe  the  white  corpuscles. 

They  are  small  protoplasmic  cells,  differing  in  no  way  from  the 
pale  round  cells  found  in  most  portions  of  the  body,  and  occur  in 
large  quantities  in  the  lymph.  For  this  reason  they  are  sometimes 
called  lymphoid  cells  or  leucocytes.  They  possess  a  finely  granular 
structure  and  nuclei,  and  these  nuclei  may  often  be  recognized 
near  the  centre  of  the  cell.  The  nuclei  may  be  made  more  marked 
by  the  action  of  certain  reagents,  notably  acetic  acid.  They  pos- 
sess an  amoeboid  movement,  and  so  are  enabled  to  migrate  not 
only  through  the  bloodvessel  wall,  but  also  through  the  tissues. 
They  are  somewhat  larger  than  the  red  disks,  and  do  not  possess 
a  cell  wall. 

What  do  you  mean  by  diapedesis  ? 

The  passage  of  the  white  blood  corpuscles  through  the  blood- 
vessel wall.  The  white  corpuscles  constantly  pass  through 
normally,  but  in  very  large  numbers  in  inflammation.  The  red 
only  under  morbid  conditions,  as  in  injury  or  inflammation. 

What  are  the  relative  positions  of  the  red  and  white  cor- 
puscles in  the  blood  stream  of  the  smaller  arterioles 
and  capillaries  ? 
The  red  move  along  rapidly  in  the  centre,  while  the  white  slowly 

roll  along  the  walls.     If  inflammation  occurs,  they  stop  and  block 


THE     BLOOD.  '!'> 

the  vessel.     The  layer  of  blood  in  which  the  white  corpuscles  lie 
is  called  the  "  still  layer." 

Where  are  the  white  corpuscles  formed  ? 
According  to  the  best  physiologists,  in  the  lymphatic  glands  and 

the  spleen,  and  very  similar  cells  develop  in  the  connective  tissues 
through  multiplication  by  division. 

What  are  their  functions  ? 

1.  To  destroy  pathogenic  bacteria  (the  phagocytosis  theory  of 
Metschnikoff). 

2.  To  take  part  in  the  process  of  blood-coagulation  by  forming 
fibrin-ferment  (thrombin). 

3.  To  aid  by  their  disintegration  the  normal  composition  of  the 
blood-plasma  as  to  proteids. 

Describe  the  red  blood  corpuscles. 

The  red  blood  corpuscles  give  the  red  color  to  the  blood  of  all 
vertebrated  animals  except  the  amphioxus,  but  arc  not  found  in 
the  blood  of  invertebrates.  They  differ  in  their  shape  in  almost 
all  animals,  in  the  mammalia  they  are  biconcave  disks.  Their 
size  differs  in  each  class  of  animals,  but  the  size  of  the  animal  has 
no  relation  to  the  size  of  the  corpuscle,  for  in  the  frog  all  the 
corpuscular  elements  are  of  great  size.  They  are  soft  and  elastic, 
and  bend  and  alter  their  shape  when  necessary  to  pass  through  a 
narrow  bloodvessel,  but  return  immediately  to  their  normal  shape 
as  soon  as  the  pressure  is  removed.  If  blood  be  withdrawn  from 
the  body,  even  for  a  few  moments,  and  then  returned  to  the  circu- 
lation, death  of  the  corpuscles  takes  place,  and  in  a  short  time 
evidences  of  their  destruction  may  be  noticed  by  the  presence  of 
haemoglobin  in  the  urine. 

What  is  one  of  the  peculiarities  of  the  red  blood  corpuscles 
outside  the  body  ? 
They  form  themselves  into  rouleaux,  which  resemble  very 
closely  the  appearance  of  a  large  number  of  coins  placed  side  by 
side.  This  peculiarity  is  due  rather  to  a  physical  law  than  to  any 
action  of  the  corpuscles  themselves,  since  it  has  been  found  that 
small  disks  of  cork  will  do  very  much  the  same  thing  when  placid 
in  water. 


26         ESSENTIALS    OF     HUMAN     PHYSIOLOGY. 

Have  the  red  blood  corpuscles  any  nuclei  ? 

Not  in  adult  life,  but  owing  to  their  biconcave  shape  the  refrac- 
tion is  such  that  under  the  microscope  a  dark  spot  is  apparently 
situated  near  their  centre.  In  the  young  embryo  nucleated  red 
corpuscles  are  found. 

Are  the  red  blood  corpuscles  few,  or  are  they  exceedingly 
great  in  number  ? 

Their  quantity  is  enormous ;  a  cubic  millimetre  contains  be- 
tween four  and  five  millions.  Approximate  mathematical  estimates 
show  that  the  red  blood  corpuscles  of  an  adult  present  an  aggre- 
gate surface  of  about  three  thousand  square  yards,  while  the 
surface  they  represent  for  the  absorption  of  oxygen  in  the  lungs 
in  one  second  is  about  eighty  square  yards. 

How  are  they  formed  ? 

In  adult  life  from  the  erythroblasts  of  the  red  marrow  of  the 
bones  ;  in  the  embryo  they  are  also  formed  in  the  liver  and  spleen. 

What  is  the  end  of  the  life  history  of  the  red  blood  cor- 
puscles ? 

Many  physiologists  regard  the  liver  as  one  of  the  chief  places 
where  the  disintegration  of  the  red  blood  corpuscles  takes  place, 
and  this  is  supported  by  the  facts  that  the  bile-pigments  are  formed 
from  haemoglobin  and  that  the  blood  of  the  hepatic  vein  contains 
fewer  red  blood  corpuscles  than  the  blood  of  the  portal  vein.  The 
spleen  is  also  regarded  as  one  of  the  organs  in  which  the  red  blood 
corpuscle  is  disintegrated.  It  is  probable  that  they  are  destroyed 
largely  while  in  the  general  circulation,  and  do  not  require  any 
special  organ  for  their  destruction. 

What  are  the  functions  of  the  red  corpuscles,  and  their  rela- 
tive number  to  the  white  corpuscles  ? 

The  function  of  the  red  blood  corpuscles  is  entirely  different 
from  that  of  the  white  blood  corpuscles.  The  red  blood  corpuscle 
contains  in  its  stroma  a  large  amount  of  haemoglobin  which,  when 
exposed  to  the  air  in  the  lung,  takes  up  oxygen,  thereby  forming 
the  chemical  compound  known  as  oxy-hsemoglobin.  By  these 
means  the  tissues,  even  in  the  most  distantly  removed  parts  of  the 


T  HE     BLOOD.  27 

body  from  the  lung,  receive  their  oxygen,  the  exchange  of  oxygen 
from  the  corpuscles  to  the  tissues  taking  place  in  the  capillaries. 
By  this  means,  oxidation,  with  the  resulting  tissue  break-down, 
and  the  development  of  beat,  takes  place  in  every  portion  of  the 
body. 

The  relative  number  of  the  white  blood  corpuscles  to  the  red 
has  been  much  discussed,  some  observers  giving  it  as  1  t<»  300, 
while  others  state  that  it  is  1  to  700.  The  proportion  varies  80 
much  in  different  parts  of  the  circulation  that  no  estimate  is  of 
any  great  value. 

Do  changes  ever  occur  in  the  relative  number  of  red  and 
white  corpuscles  in  health? 
Very  frequently,  since  many  circumstances  arising  in  every- 
day life  may  produce  great  changes  in  this  respect.  The  varia- 
tion may  be  all  the  way  from  1  in  50  to  1  in  1200.  Pregnancy 
decreases  the  proportion ;  meals  also  have  a  very  powerful  effect 
on  their  relative  numbers.  Certain  diseases  also  alter  the  pro- 
portion greatly. 

What  is  haemoglobin  ? 

It  is  the  substance  which  gives  the  red  color  to  the  corpuscles, 
and  carries  by  their  aid  the  oxygen  to  the  tissues. 

What  is  haematin? 

A  result  of  the  decomposition  of  haemoglobin  by  acids  or  alka- 
lies in  the  presence  of  oxygen. 

Haemin  is  a  compound  of  haematin  and  HC1. 

Haematoidin  is  a  crystal lizable  substance  found  in  old  blood- 
clots  and  comes  from  haemoglobin.  It  is  identical  with  the  bile- 
pigment,  bilirubin. 

What  are  the  gases  of  the  blood  ? 

Chiefly  oxygen,  carbonic  acid,  and  nitrogen.  The  oxygen  exists, 
as  before  stated,  in  chemical  combination  with  the  haemoglobin, 
and  is  also  in  small  amounts  simply  absorbed  by  the  blood  plasma. 

Carbonic  acid  occurs  in  less  amount  in  arterial  blood  than  in 
venous  blood. 

Nitrogen  exists  in  the  blood  in  very  small  amount,  and  appears 
to  be  simply  absorbed. 


28  ESSENTIALS     OF     HUMAN     PHYSIOLOGY. 

From  100  volumes  of  blood  may  be  obtained — 

0.  C02.  N. 

Of  arterial  blood  (from)       20  vols       .  40  vols.  .    .  1  to  2  vols. 

a  large  artery),  ) 

Of  venous  blood  (from  ]  8_^     «  45     «  1  to  2    " 

rigbt  side  of  heart),  i 

Does  C02  unite  with  the  haemoglobin? 

No.  It  is  held  in  solution  chiefly  by  the  plasma,  and  in  very 
small  amount  in  the  red  blood  corpuscles. 

What  is  the  quantity  of  the  blood  ? 

The  quantity  of  blood  in  a  human  male  adult  is  equal  to  one- 
thirteenth  part  of  the  body  weight. 

Coagulation  of  Blood. 

Blood,  on  being  withdrawn  from  a  vessel,  is  perfectly  fluid,  but 
rapidly  becomes  thick,  and  then  forms  a  clot  resembling  a  solid 
gelatinous  mass. 

What  is  this  clotting  due  to  ? 

The  formation  of  fibrin,  in  part  at  least,  from  fibrinogen. 

Does  fibrin  exist  already  formed  in  the  blood  ? 

No. 

How  is  it  produced  ? 

There  is  no  perfectly  satisfactory  theory  of  coagulation.  The 
most  generally  accepted  one  is  that  of  Hammarsten,  that  the  reac- 
tion between  fibrinogen  and  fibrin-ferment  (thrombin)  produces 
fibrin. 

It  is  also  necessary  that  calcium  salts  be  present,  for  without 
them  fibrin  cannot  be  formed  from  fibrinogen.  Fibrin-ferment 
does  not  exist  in  the  blood  until  after  it  is  shed ;  then  the  disinte- 
gration of  the  white  blood  corpuscles  occurs  and  the  ferment  is 
formed. 

How  is  the  clot  made  up  ? 

The  fibrin  forms  in  fibrils,  which  entangle  the  blood  corpuscles 
as  in  a  spider's  web,  and  thereby  form  a  complete  blood-clot. 


COAGULATION    OF    BLOOD.  29 

The  blood  in  the  body  is  made  up  as  follows : 

Blood 
I 


Plasma  Oorpnsclee  (red  and  white) 

I  I 

Water  Fibrin-ferment 

I 

Salts 

I 

Serum-albumin 

Paraglnl.iiliii 

Fibrinogen. 

Blood  when  it  has  undergone  coagulation  is  as  follows: 

Blood 
I 

r  j 

Plasma  Corpuscles,  red  and  whits 

I 


I 
Clot 

I 
Containing  tibrin,  corpuscles,  and  serum. 

What  chp'^ges  take  place  after  the  clot  is  formed? 

The  clot  leaves  the  sides  of  the  vessel,  and  on  its  surface  there 
appear  small  transparent  drops  of  yellowish  liquid  known  as  serum. 
These  drops  running  together  form  a  layer  of  yellowish  fluid. 

In  what  way  is  the  serum  expelled  from  the  clot? 

The  fine  fibrils  of  fihrin  ramifying  all  through  the  clot  contract, 
and  squeeze  out  the  serum.  These  fibrils  also  entangle  the 
corpuscles. 

How  long   does   this  contraction  and  displacement  of  the 
serum  last? 
From  twenty-four  to  thirty-six  hours. 

How  is  blood  defibrinated? 

By  beating  it  with  twigs  or  a  glass  rod.     The  fibrin  adh<  n 
sticky  masses   to   the  rod-,  and    the  remaining  fluid  will   not  clot. 
The  corpuscles  are  left,  most  of  them  in  the  serum. 


30  ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  conditions  hinder  or  delay  coagulation? 

The  addition  of  small  quantities  of  alkalies  or  of  concentrated 
solutions  of  neutral  salts  of  alkalies,  notably  magnesic  sulphate; 
the  addition  of  egg-albumin,  syrup,  glycerine,  and  much  water; 
and  by  covering  the  blood  with  oil,  or  by  cold  at  freezing  point. 

What  hastens  coagulation  ? 

Coagulation  is  accelerated  by  contact  with  any  foreign  body,  by 
heating  from  39°  to  55°  C,  and  by  constant  agitation. 

What  do  you  mean  by  the  buffy  coat? 

In  blood  which  is  drawn  from  a  body  during  inflammation  the 
fibrin  coagulates  slowly,  and  the  corpuscles  subside  to  the  bottom 
of  the  vessel,  so  that  the  upper  stratum  of  the  clot  is  not  red  but 
only  yellowish,  containing  scarcely  any  red  blood  corpuscles. 
This  occurs  physiologically  in  horses'  blood. 

What  prevents  coagulation  of  the  blood  in  the  bloodvessels? 

This  is  not  positively  known  ;  some  relationship  exists  between 
living  tissues  and  the  blood. 

Under  what  circumstances  does  clotting  in  the  bloodvessels 
occur  ? 

As  soon  as  the  endothelial  layer  of  the  bloodvessels  is  in  any 
way  injured. 

How  long   after   death  does   the  blood   coagulate   in  the 
body? 

From  ten  to  twenty-four  hours. 

Do  pathological  changes  ever  take  place  in  the  blood  ? 

Yes.  Plethora  is  an  increase  in  the  quantity  and  quality  of  the 
blood,  the  red  corpuscular  elements  being  greatly  increased  in 
number 

Anosmia  is  a  decrease  in  the  corpuscular  elements  of  the  blood, 
without  necessarily  any  increase  in  the  liquids. 

Leucocythcemia  or  leukaemia  is  a  term  applied  to  a  condition  in 
which,  together  with  other  changes,  the  white  blood  corpuscles  are 
very  much  increased  in  number,  from  10,000  to  1,000,000  in  a  cubic 
millimetre  of  blood.  In  some  cases  the  white  corpuscles  are  as 
numerous  as  the  red. 


TIIE    HEART.  31 

Uni'iiiin  cannot  be  considered  a  disease  of  the  blood,  but  simply 
an  accumulation  of  urea  in  that  fluid,  owing  to  kidney  disorders. 

THE  HEART. 

What  is  the  simplest  form  of  heart  ? 

The  early  embryonic  heart,  which  is  merely  a  tubular  heart 
with  one  cavity  and  an  outer  circular  and  inner  longitudinal 
layer  of  fibres. 

Does  the  muscular  fibre  of  this  tubular  heart  afford  walls 
to  both  the  auricle  and  ventricle  after  the  septum  is 
formed  ? 

Yes,  but  the  muscular  fibres  of  the  auricle  do  not  change  to  any 
extent,  while  the  ventricular  fibres  become  much  altered. 

What  separates  the  auricular  fibres  at  this  time  from  the 
ventricular  fibres  ? 
Fibrocartilaginous  rings  at  the  opening  in  the  septum. 

What  is  the  function  of  the  heart  ? 
To  propel  blood  through  the  body. 

How  many  cavities  has  it  ? 
Four. 

What  is  the  weight  of  the  adult  male  heart  ? 
Nine  ounces. 

What  is  the  weight  of  the  adult  left  ventricle  as  compared 
to  the  right? 
About  twice  as  heavy. 

What  is  the  difference  between  the  right  and  left  side  of 
the  heart  ? 

The  right  side  of  the  heart  takes  the  venous  blood  from  the 
vena  cava?  and  pumps  it  through  the  lungs  to  the  left  side  of  the 
heart.  This  circulation  is  much  more  limited,  of  course,  than  that 
produced  by  the  left  side,  and  is  known  as  the  pulmonic  circulation. 


32  ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

The  left  side  of  the  heart  receives  the  arterialized  blood  from  the 
lung  and  drives  it  into  the  general  arteries.  This  is  known  as  the 
systemic  circulation. 

Which  is  the  strongest,  the  right  or  left  side  of  the  heart  ? 

The  left  side  is  not  only  much  stronger,  but  its  walls  are  much 
thicker  on  account  of  the  greater  amount  of  work  which  it  is 
forced  to  perform. 

What  is  the  difference  between  the    contraction  of  the 
auricles  and  the  contraction  of  the  ventricles  ? 

The  contraction  of  the  ventricles  takes  place  synchronously 
from  all  sides,  so  that  the  pressure  within  is  equal  in  any  direc- 
tion. The  auricles  contract  peristaltically  from  the  opening  of 
the  supplying  vessel  toward  the  auriculo-ventricular  orifice. 

Which  have  the  thickest  walls,  the  ventricles  or  the  auricles  ? 

The  ventricles,  owing  to  the  greater  force  which  they  are  re- 
quired to  put  out. 

What  is  the  function  of  the  auricles  ? 

To  act  as  a  reservoir  for  the  blood  while  the  ventricles  are 
contracting,  and  force  the  blood  through  the  auriculo-ventricular 
openings,  and  so  supply  the  ventricles. 

Has  the  heart  any  suction  power  enabling  it  to  aid  the 
circulation  not  only  by  pushing  but  by  sucking  ? 
According  to  the  latest  researches  it  has  not.1 

What  is  the  endocardium  ? 

The  membrane  lining  the  heart. 

Is  it  limited  to  this  viscus  or  not  ? 

It  is  continuous  with  the  endothelial  lining  of  the  bloodvessels. 

Has  the  endocardium  bloodvessels 
No,  it  has  not. 

1  The  muscular  arrangement  of  the  heart  is  probably  already  known  to  the  student ; 
if  not,  he  must  turn  to  his  anatomical  text-books. 


THE    HEART.  33 

What  are  the  valves  of  the  heart  ? 

They  are  fibrous  flaps  arranged  in  one  of  two  ways,  which  open 
and  shut  the  orifices  which  they  guard.  The  edges  of  the  auriculo- 
ventricular  valves  are  attached  by  what  are  known  as  chordae 
tendineae  to  the  walls  of  the  ventricles. 

In  what  way  are  the  valves  attached  to  the  heart  ? 

They  are  fixed  to  the  fibrous  rings,  made  up  of  yellow  elastic 
tissue  and  fibrous  tissue  which  surround  the  openings. 

Do  the  valves  have  any  muscular  fibres  in  them  ? 

According  to  Reid  and  Gussenbauer,  the  auriculo-ventricular 
valves  do;  the  fibres  come  from  the  auricles. 

Have  the  valves  bloodvessels  ? 

None  near  the  edges.     Only  as  far  as  the  muscular  fibres  run. 

What  is  the  function  of  the  valves  ? 

To  prevent  the  regurgitation  of  blood  from  a  heart  cavity,  or 
bloodvessel,  back  into  the  area  from  which  it  has  been  propelled. 

What  two  sets  of  valves  have  we  ? 
The  auriculo-ventricular  and  semilunar. 

Where  are  they  situated  ? 

The  semilunars  guard  the  opening  of  the  aorta  and  pulmonary 
artery. 

At  the  right  auriculo-ventricular  orifice  we  have  the  tricuspid 
valve,  at  the  left  auriculo-ventricular  we  have  the  mitral  or 
bicuspid  valve. 

How  many  cusps  make  up  the  semilunars  ? 
Three  at  each  opening. 

Are  there  any  valves  at  the  opening1  of  the  cavse  into  the 
right  auricle  ? 
No. 

Why  are  they  not  needed  ? 

Because  the  peristaltic  action  of  the  auricle  prevents  a  tendency 
to  regurgitation,  except  in  rare  conditions.     For  the  same  reason 

3 


34:         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

we  have  no  valve  at  the  opening  of  the  pulmonary  vein  into  the 
left  auricle. 

What  are  the  chordae  tendineae  ? 

The  chordae  tendineae  are  small  bands  running  from  the  mus- 
cular fibres  of  the  heart  wall  to  the  edges  of  the  valves. 

What  is  the  function  of  the  chordae  tendineae  ? 

To  prevent  the  everting  of  the  auriculo-ventricular  valves  into 
the  auricles  by  a  sudden  pressure  of  blood  during  ventricular 
systole. 

In  what  way  is  the  heart  nourished  ? 

By  means  of  its  coronary  arteries,  which  are  peculiar  in  that 
they  do  not  anastomose. 

Where  do  these  arteries  arise  ? 

From  the  aorta  near  the  sinus  of  Valsalva. 

What  is  the  condition  of  the  openings  of  these  arteries 
during  the  period  of  systole  ? 
They  are  closed  by  the  aortic  valves. 

Are  the  veins  of  the  heart  called  coronary  veins  ? 
No.    They  are  called  cardiac  veins. 

What  other  cause  produces  an  onward  flow  of  the  blood 
through  the  coronary  arteries  than  the  vis  a  tergo 
from  the  systolic  driving  out  of  blood  into  the 
aorta  ? 

The  lateral  pressure  exercised  on  the  vessels  by  tha  surrounding 
heart  muscle. 

What  effect  has  ligation  of  one  or  both  coronary  arteries? 

The  heart  in  two  minutes  changes  its  rhythmical  movements 
into  twitchings  and  soon  ceases  all  movement. 

What  is  this  change  due  to  ? 

Both  to  failure  of  nutrition  and  to  failure  in  the  removal  of 
effete  matters  from  the  heart  by  the  blood,  as  a  consequence  of 
which  the  heart  is  poisoned  by  the  poisons  generated  by  itself. 


THE    HEART.  35 

What  are  the  columnse  carneae  ? 

They  are  small  ridges  of  muscular  tissue  lying  on  the  ventricular 
wall. 

What  are  the  musculi  papillares  ? 

They  are  small  teat-like  muscular  projections  arising  from  the 
inner  portion  of  the  ventricular  wall,  to  which  the  chorche  tendinese 
are  generally  attached. 

What  is  their  function  ? 

As  the  ventricle  contracts  and  the  heart  shortens  they  pull  the 
chordae  tendineae  tense  and  take  up  the  slack,  as  it  were. 

In  what  way  does  the  blood  circulate  through  the  heart? 

Entering  the  right  auricle  from  the  cavse,  it  passes  through  the 
right  auriculo-ventricular  opening  into  the  right  ventricle,  then 
through  the  pulmonary  artery  into  the  lungs,  from  the  lungs 
through  the  pulmonary  veins  to  the  left  auricle,  and  through  the 
left  auriculo-ventricular  orifice  to  the  left  ventricle,  from  the 
ventricle  through  the  aorta,  and  so  on  through  the  arterial  system. 

How  much  blood  is  sent  out  of  the  left  ventricle  ordinarily 
in  the  adult  at  one  contraction  ? 
About  four  to  six  ounces. 

How  much  force  does  the  heart  put  out  at  each  systole  ? 

Enough  to  lift  three  foot-pounds.1  Of  this  the  left  ventricle 
does  two  and  a  quarter  pounds.  In  twenty-four  hours  the  heart 
puts  out  enough  force  to  lift  one  hundred  and  twenty-four  foot- 
tons,  or  enough  to  lift  one  ton  one  hundred  and  twenty-four  feet. 

What  are  the  movements  of  the  heart  ? 

The  chief  movements  are  those  of  contraction,  or  systole,  and 
expansion,  or  diastole. 

The  two  auricles  contract  synchronously,  thereby  filling  the 
ventricles,  then  the  ventricles  contract  together,  and  then  follows 
diastole.     Following  ventricular  diastole  there  is  &  pause. 

1  A  foot-pound  represents  the  force  required  to  lift  one  pound  one  foot. 


36        ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

Systole,  diastole,  and  the  pause,  therefore,  make  up  one  cardiac 
revolution  or  cycle. 

Does  the  heart  change  its  position  during  contraction  or 
expansion  ? 
Yes,  somewhat ;  for,  with  contraction,  the  base  of  the  heart  de- 
scends, the  base  of  the  ventricle  goes  toward  the  left  but  the  whole 
heart  rotates  a  little  to  the  right,  and  the  apex  is  tilted  a  little  for- 
ward.    The  vertical  movement  of  the  apex  amounts  to  nothing. 

At  what  time  does  the  impulse  of  the  heart  take  place 
against  the  chest  ? 
During  systole. 

What  is  the  object  of  the  pericardium  ? 

It  acts  as  a  protecting  membrane  surrounding  the  heart.  The 
visceral  layer  covers  the  heart  and  is  in  turn  covered  by  a  reflexion 
of  the  membrane  which  forms  the  parietal  layer.  These  two 
surfaces  secrete  a  sufficient  quantity  of  liquid  to  lubricate  their 
surfaces  as  they  move  on  one  another. 

When  the  heart  is  slowed  or  quickened,  is  the  change  in 
speed  due  to  a  change  in  systole  or  diastole,  or 
both? 

Systole  remains  unaltered,  diastole  is  prolonged  when  slowing 
occurs,  shortened  when  quickening  occurs. 

How  many  heart  sounds  have  we? 
Two;  the  long,  dull  "lub,"  and  the  short,  sharp  "dup." 

What  are  the  sounds  of  the  heart  due  to  ? 

The  first  sound  is  due  to  the  vibration  of  the  auriculo-ven- 
tricular  valves  made  tense  by  the  systolic  force  of  the  ventricles, 
and  also  the  sudden  contraction  of  the  muscular  fibres  of  the  heart 
walls.  The  striking  of  the  apex  against  the  chest  wall  does  not 
even  help  the  first  sound,  since  it  can  be  heard  after  the  wall  is 


THE    HEART.  37 

removed.    The  second  sound  is  produced  by  the  closure  of  the 
aortic  valves. 

At  what  rate  does  the  heart  beat  ? 

Before  birth,  per  minute,  the  beats  are  140-150. 

During  first  year,  per  minute,  the  beats  are  125-135. 

1  Miring  third  year,  per  minute,  the  beats  are  95-100. 

During  eighth,  ninth,  and  tenth  to  fourteenth  year,  85-90. 

In  the  adult,  about  72. 

In  very  old  age,  or  decrepitude,  the  pulse  once  more  becomes  fast. 

In  which  sex  is  the  pulse  most  rapid  ? 
In  females. 

What  effect  has  posture  on  the  pulse  ? 

The  erect  posture  causes  a  more  rapid  pulse  than  the  recum- 
bent. 

What  other  conditions  influence  its  rate  ? 

Respiratory  changes,  drinking  water  in  small  repeated  swallows, 
and  many  similar  conditions. 

What  is  the  intrinsic  nervous  mechanism  of  the  heart  ? 

The  intrinsic  nervous  mechanism  of  the  heart  consists  in  three 
centres,  which  have  been  proved  to  exist  in  the  heart  of  the  frog, 
and  are  generally  received  as  the  centres  for  the  mammalian  heart. 
The  three  centres  are: 

1.  The  motor  ganglion,  or  that  of  Remak. 

2.  The  accelerator,  or  second  motor  ganglion,  or  that  of  Bidder. 

3.  The  inhibitory  ganglion,  or  that  of  Ludwig. 
Fig.  1.  will  serve  to  illustrate  the  matter  : 

The  motor  ganglion  (a)  sends  out  through  its  radiating  fibres 
impulses  which  drive  the  heart. 

The  accelerator  motor  ganglion  {b),  when  it  acts,  quickens  the 
irradiation  of  these  impulse-. 

The  inhibitory  ganglion  (c)  prevents  the  heart  from  beating  too 
fast. 


38         ESSENTIALS    OF    HUMAN     PHYSIOLOGY. 

Fig.  1. 


a.  The  motor  centre,  that  of  Remak.  6.  The  accelerator  motor  centre,  that  of  Bidder 
c.  The  inhibitory  centre,  that  of  Ludwig.  <l.  The  accelerator  nerves,  e.  The  pneumo- 
gastric  or  inhibitory  nerves.     The  arrows  represent  direction  in  which  impulses  travel 

What  keeps  up  the  contraction  of  the  muscle  ? 

The  constant  circulation  of  the  blood  over  the  endothelium, 
thereby  stimulating  and  sending  reflex  impulses  to  the  motor 
ganglion. 

What  are  the  extrinsic  cardiac  nerves  ? 

The  accelerators  and  the  pneumogastric  or  inhibitory  nerves, 
which  arise  in  the  base  of  the  brain  and  are  governed  by  centres 
there. 

What  is  their  function  ? 
They  govern  the  ganglia  in  the  heart  muscle. 

Are    the    pneumogastric    nerves    and    the    accelerators, 
strictly  speaking,  antagonists  ? 
They  are  not,  for  the  accelerators  do  not  act  all  the  time,  while 
the  pneumogastrics  do,  and  the  vagi  can  always  overcome  readily 
any  accelerator  influence. 

What  effect  on  the  heart  has  stimulation  of  the  pneumo- 
gastrics 
It  slows  the  pulse  and  produces  large  and  full  diastole. 


THE    HEART.  39 

What  effect  has  section  of  the  vagus  ? 
It  produces  an  exceedingly  rapid  pulse. 

What  effect  has  stimulation  of  the  accelerators  ? 
Stimulation  of  the  accelerators  makes  a  very  rapid  pulse. 

What  is  the  depressor  nerve,  and  what  is  its  function  ? 

The  depressor  nerve  is  given  off  from  the  superior  laryngeal 
nerve  and  the  trunk  of  the  vagus  in  the  rabbit,  and  passes  into  the 
cardiac  plexus.  It  conducts  impulses  from  the  heart  to  the  vaso- 
motor centre,  and  lowers  the  activity  of  that  centre,  thereby  relax- 
ing the  bloodvessels  somewhat.  In  this  way  the  heart  when  over- 
worked, owing  to  the  increased  resistance  of  high  blood-pressure 
(vasomotor  spasm),  can  be  relieved  as  soon  as  is  necessary. 

What  is  the  function  of  the  so-called  pressor  fibres  of  the 
laryngeal  nerves  ? 
They  stimulate  the  vasomotor  centre,  causing  a  rise  of  blood- 
pressure.     They  are,  therefore,  the  direct  opponents  of  the  depres- 
sor fibres. 

What  are  the  functions  of  the  bloodvessels  ? 

The  bloodvessels  carry  blood  to  and  from  the  various  tissues  and 
organs.     They  are  divided  up  into  three  divisions,  known  as:  1, 

Fig   2. 


Capillary  network  of  fat  tissue.    (Klein.) 

arteries  and  arterioles;  2,  capillaries;  3,  veins.  Of  these  three, 
the  capillaries  are  most  important  in  their  function,  since  they  not 
only  carry  blood,   but    owing  to  the  peculiarity  of  their  walls, 


40         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

bring  the  blood  into  intimate  relation  with  the  tissues.  The  fluid 
which  escapes  from  the  capillaries  is  known  as  lymph,  and  the 
function  of  lymph  is  to  irrigate  and  nourish. 

What  is  the  difference  between  arteries  and  veins  ? 

Arteries  differ  from  veins  in  having  thicker  walls,  owing  to  a 
greater  development  of  their  outer  coats. 

Remember!  The  fact  that  arteries  do  not  contain  valves  is  not 
a  differential  point,  since  some  veins  contain  no  valves. 

Also  that  they  are  not  differentiated  by  the  kind  of  blood  they 
carry,  but  by  their  structure  ;  the  pulmonary  artery  carries  venous 
blood,  while  the  pulmonary  veins  carry  arterial  blood. 

How  many  coats  have  the  arteries  ? 

They  have  three  coats,  known  as  the  outer,  or  tunica  advent  iti  a  ; 
the  middle,  or  tunica  media;  the  inner,  or  tunica  intima.  The  last 
of  these  is  made  up  of  transparent  endothelium,  composed  of 
irregular,  long,  fusiform  cells  held  together  by  a  cement  substance 
which  is  stained  black  by  nitrate  of  silver  (AgN03).  Outside  the 
endothelial  coat  lies  a  very  thin,  more  or  less  fibrous  layer,  the 
sub-endothelial ;  and  outside  of  this  is  the  elastic  lamina,  which  in 
the  smallest  arteries  amounts  to  nothing  more  than  a  structureless 
or  fibrous  membrane,  whilst  in  the  other  vessels  its  function  is 
most  important.  It  is  known  as  the  fenestrated  membrane.  The 
tunica  media  contains  much  unstriped  muscular  fibre,  which 
increases  in  amount  as  the  vessel  grows  larger.  Most  of  these 
fibres  are  circular,  completely  surrounding  the  vessel,  while  a 
much  smaller  number  run  longitudinally.  The  tunica  adventitia, 
or  the  outer  coat  in  the  smallest  arteries,  is  a  structureless  mem- 
brane which  changes  into  a  fibrous  membrane  as  the  vessel 
increases  in  size. 

What  are  the  functions  of  these  coats  ? 

The  endothelial  layer  forms  a  smooth  surface  over  which  the 
blood  may  pass,  and  the  importance  of  this  will  be  understood 
when  it  is  remembered  that  rough  surfaces  aid  in  the  coagulation 
of  the  blood.  The  muscular  coat  regulates  the  amount  of  blood 
received  by  each  part  and  governs  the  elastic  coat.    This  is  neces- 


THE    HEART.  41 

sary,  since  it  is  manifest  that  the  heart  cannot  regulate  the  blood- 
supply  of  each  portion  of  the  body. 

Does    the    muscular    coat    aid    in    the    propulsion  of  the 
blood  ? 

No ;  it  must  be  distinctly  remembered  that  in  the  higher 
animals, particularly  in  man,  the  muscular  coat  probably  aids  very 
slightly  in  the  propulsion  of  blood. 

In   what   way   do   these    coats  aid   in  arresting-  hemor- 
rhage ? 

The  muscular  coat  aids,  in  conjunction  with  the  elastic  coat,  in 
the  prevention  of  extensive  hemorrhage  by  contracting  the  open- 
ing in  the  bloodvessel,  turning  in  its  edges  so  that  the  opening  is 
greatly  decreased  in  calibre. 

What  other  function  has  the  elastic  coat  ? 

A  more  important  function  of  the  elastic  coat  is  the  prevention 
of  sudden  pressure  in  any  portion  of  the  body  by  yielding  partially 
to  a  sudden  strain  or  controlling  a  tendency  to  too  great  a  dilata- 
tion. It,  therefore,  equalizes  blood-pressure  during  diastole  and 
systole,  and  were  it  not  for  this  important  coat  the  arteries  would 
be  entirely  emptied  during  diastole  and  filled  to  bursting  during 
systole. 

What  is  the  function  of  the  outer  fibrous  coat  of  the  larger 
bloodvessels  ? 

To  protect  the  bloodvessels  from  injuries  from  the  exterior  and 
to  give  the  bloodvessel  walls  support.  If  it  were  not  for  the  fibrous 
coat  a  ligature  applied  to  a  vessel  would  cut  through. 

What  have  we   in   some   veins    which    do    not    occur    in 
arteries  ? 

Valves  which  flap  back  against  the  wall  of  the  vessel  as  the 
blood  flows  onward,  but  which  prevent  any  reflux  .should  the 
current  be  reversed  by  any  cause. 


42         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

How  are  these  valves  arranged,  singly  or  in  pairs  ? 
In  pairs. 

[s   there   any   difference  in  the   capacity   of  the   various 
portions  of  the  vascular  system  ? 

The  combined  calibre  of  the  branches  of  an  artery  exceed  in 
their  capacity  that  of  the  parent  trunk,  and  so  soon  as  the  muscular 
coat  of  an  artery  is  past  the  capacity  of  the  vascular  system  is 
enormously  increased.  The  capillaries  are  capable  of  holding 
eight  hundred  times  as  much  blood  as  the  aorta.  The  veins 
diminish  in  area  as  they  come  toward  the  heart,  whilst  the  arteries 
increase  as  they  go  toward  the  periphery.  The  capacity  of  a  vein 
is  always  greater  than  that  of  a  corresponding  artery :  even  at  the 
heart  the  capacity  of  the  venae  cavse  is  twice  as  great  as  that  of 
the  aorta. 

Fig.  3. 


Diagram  intended  to  give  an  idea  of  the  aggregate  sectional  area  of  the  different 
parts  of  the  vascular  system.  A.  Aorta.  C.  Capillaries.  V.  Veins.  The  transverse 
measurements  of  the  shaded  part  maybe  taken  as  the  width  of  the  various  kinds  of 
vessels,  supposing  them  to  be  fused  together.     (Yeo.) 


What  do  you  mean  by  blood-pressure  ? 

The  pressure  under  which  the  blood  stream  is  kept  by  the  action 
of  the  heart  and  the  walls  of  the  bloodvessels. 


THE    HEART.  43 

Is  the  blood  pressure  always  constant  in  man  and  animals  ? 
The  blood  pressure  varies  from  many  causes,  and  differs  in  nearly 
all  animals.  In  the  rabbit  it  can  support  a  column  of  mercury 
from  two  to  three  and  a  half  inches  in  height,  in  the  dog  from  four 
to  five  and  a  half  inches,  in  the  horse  from  eight  to  twelve  inches, 
while  in  man  the  pressure  will  hold  a  column  of  mercury  as  high 
as  five  and  three-fourths  inches.  The  pressure  in  the  human  aorta 
is  estimated  at  four  pounds  and  four  ounces,  in  the  horse  eleven 
pounds  and  nine  ounces,  in  the  radial  artery  of  man  at  four  drachms, 
in  the  pulmonary  artery  two  pounds  and  two  ounces.  But  it  must 
be  remembered  that  these  figures  represent  the  maximum  amounts 
at  the  moment  of  ventricular  systole.  The  pressure  is  least  in  the 
capillaries,  greatest  in  the  aorta.  The  venous  pressure  is  only 
one-tenth  that  of  the  arterial  pressure. 

What  is  the  influence  of  the  nervous   system   on  blood 
pressure  ? 
Nerves  supply  all  the  arteries  and  arterioles,  and  even  the  capil- 
laries and  veins,  and  belong  to  the  so-called  sympathetic  system. 

What  are  these  nerves  called  ? 
Vaw-motor  nerves. 

How  are  they  arranged  and  governed  ? 

By  a  centre  in  the  medulla  oblongata  known  as  the  vnso-motor 
centre,  which  is  situated  near  the  calamus  scriptorius  and  the  cor- 
pora quadrigemina,  the  tension  of  the  vascular  system  is  governed. 
Fibres  from  this  centre  pass  down  in  the  neck  through  the  spinal 
cord,  and  find  exit  with  the  anterior  roots  of  the  spinal  nerves. 
The  vaso-motor  centre  is  probably  always  at  work,  and  to  aid  it  we 
have  scattered  through  the  spinal  cord,  and  in  various  portions  of 
the  body,  lesser  centres  under  its  control,  but  capable  of  originating 
impulses  themselves. 

What  proof  have  we  that  this  is  so  ? 

If  the  cervical  sympathetic  be  cut  on  one  side  in  the  rabbit,  or 
in  any  animal,  that  side  of  the  head  becomes  very  rapidly  deeply 
suffused  and  congested,  and  remains  in  this  condition  tor  many 
hours.     Finally,  however,  the  color  returns  almost  to  normal,  and 


44         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

congestion  goes  down.  The  first  dilatation  was  due  to  the  fact  that 
the  governing  centre  in  the  medulla  by  the  section,  was  cut  off  from 
that  side,  and  the  minor  centre  not  being  accustomed  to  send  out 
powerful  impulses,  is  unable  to  govern  its  tributary  bloodvessels. 
In  a  short  time,  however,  the  local  centre  gathers  power,  and  once 
more  exerts  not  only  its  previous  influence  over  the  vascular  supply 
of  that  side,  but  also  is  enabled  to  supplement  the  action  of  the 
higher  centre  in  the  medulla,  which,  before  the  section,  constantly 
aided  it  in  its  efforts. 

What  effect  has  stimulation  of  the  vaso-motor  system  on 
blood  pressure  ? 
It  raises  it  by  contraction  of  the  bloodvessels  all  over  the  body. 

What  effect  has  depression  of  the  vaso-motor  system  on 
blood  pressure  ? 

It  lowers  it  by  dilatation  of  the  bloodvessels. 

What  effect  has  division  of  a  vaso-motor  nerve  on  its 
tributary  vessels  ? 
It  produces  palsy,  or  relaxation,  of  its  tributary  muscles  in  the 
wall  of  the  bloodvessel,  and,  as  a  consequence,  a  local  or,  if  the 
vessels  are  large  enough,  indirectly  a  general  fall  in  blood  pressure, 
by  drawing  a  large  amount  of  blood  from  the  general  system. 
Stimulation  of  a  nerve,  on  the  other  hand,  produces  a  contraction 
of  these  muscles  and  a  rise  of  pressure.  Blushing  is  a  good  example 
of  vaso-motor  disturbance  of  the  nervous  apparatus  governing  the 
vascular  system. 

What    effect   has    galvanization    of  a   sensory  nerve   on 
general  blood  pressure  ? 

It  raises  it. 

What  effect  has  it  on  bloodvessels  of  a  leg  in  which  the 
sensory  nerve  is  galvanized  ? 

It  dilates  them  and  locally  lowers  pressure. 

What  effect  has  asphyxia  on  blood  pressure? 

It  increases  it  by  stimulation  of  the  vaso-motor  centre  in  the 
medulla  by  the  increased  amount  of  C02  in  the  blood. 


THE    HEART  45 

What  effect  has  section  of  the  spinal  cord  on  blood  pres- 
sure ? 
It  produces  a  great  fall  in  pressure,  due  to  the  cutting  off  of  the 
vaso-raotor  centre  in  the  medulla  from  the  vascular  system  all 
through  the  body. 

What  effect  has  paralysis  of  the  vaso-motor  nerves  supply- 
ing the  abdominal  bloodvessels  ? 
A  general  fall  in  blood  pressure  all  over  the  body. 

Why  is  this  so  ? 

Because  these  bloodvessels  are  capable  of  holding  all  the  blood 
in  the  body,  and  so  starve  the  rest  of  the  vascular  system. 

What  other  causes  increase  arterial  pressure  ? 

Increased  heart  action,  whereby  more  blood  is  driven  out  into 
the  bloodvessels  in  a  given  space  of  time.  The  increase  in  heart 
action  may  be  by  increased  rate  or  force,  the  result  is  tbe  same. 

What  are  the  physical  forces  of  the  circulation  ? 

Liquid  always  goes  away  from  pressure,  and  the  pressure  depends 
on  the  ease  of  escape  and  the  forces  from  behind.  If  a  tube  be 
elastic,  and  its  distal  end  open  and  small,  it  will  be  found  that 
though  the  liquid  enters  it  in  jerks  at  the  proximal  end,  it  will 
leave  the  distal  end  in  a  steady  stream,  but  if  the  tube  is  rigid  the 
liquid  moves  in  jerks  along  its  whole  length.  This  is  the  key  to  the 
circulation. 

Under  what  conditions  is  the   blood  placed  after  being 
driven  out  of  the  ventricle  into  the  arterial  system? 

Just  before  the  arteries  are  changed  into  capillaries  they  are 
known  as  arterioles;  it  is  in  these  arterioles  that  we  still  have  the 
muscular  coat  quite  powerfully  developed  and  governed  by  the 
vaso-motor  system.  These  muscular  coats  are  kept  at  a  certain 
degree  of  tonicity,  producing  thereby  a  considerable  narrowing 
of  the  blood  paths,  and  they,  therefore,  prevent  the  blood  from 
flowing  out  into  the  capillary  system  too  rapidly.  On  the  other 
hand,  the  force  given  to  the  blood  by  the  heart  has  so  distended 


46         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

the  arterial  system,  particularly  in  the  larger  trunks,  that  the 
elastic  coats  have  been  greatly  stretched,  and  no  sooner  does 
the  pressure  from  the  heart  muscle  cease  than  they  contract  on 
the  blood.  Pressed  upon  in  this  manner  on  all  sides,  the  blood 
endeavors  to  find  some  mode  of  exit,  and  is  prevented  from 
regurgitating  back  into  the  ventricle,  in  health,  by  the  valves 
at  the  aortic  opening.  As  a  consequence,  the  blood  obeys  the 
physical  law  already  mentioned,  and  passes  in  the  direction  of  least 
resistance,  namely,  through  the  contracted  arterioles. 

What  is  the  function,  therefore,  of  the  arterioles  ? 

To  prevent  too  rapid  a  flow  into  the  capillary  system,  which,  if 
permitted,  would  immediately  starve  both  the  arteries  and  veins  of 
their  proper  amount  of  blood,  since,  as  before  noted,  the  capacity 
of  the  capillaries  is  extremely  great. 

What  aids  blood  flow  in  the  capillaries  ? 

Capillary  attraction  and  pressure  due  to  muscular  movements  of 
the  body.     Also  to  the  action  of  the  heart  and  arterial  coats. 

What  aids  blood  flow  in  the  veins  ? 

Lateral  pressure  exerted  by  contraction  of  the  voluntary  mus- 
cles of  the  body,  the  indirect  action  of  the  valves  in  the  veins,  and, 
to  a  slight  degree,  the  heart  force.  Also,  the  suction  produced  by 
movements  of  the  thorax  in  respiration  (not  the  heart). 

Does  the  blood  find  it  more  difficult  to  return  through  the 
veins  than  to  descend  through  the  arteries  ? 
No ;  the  circulation  in  this  respect  resembles  a  U-shaped  tube 
filled  with  mercury,  in  which  the  column  rises  on  one  side,  due  to 
pressure  or  displacement  on  the  other.  In  other  words,  the  blood 
descending  in  the  femoral  artery  shoves  the  blood  up  the  corre- 
sponding vein. 

Is  there  difference  in  the  rapidity  of  the  flow  of  the  blood 
in  the  arteries,  capillaries,  and  veins  ? 
Yes;  in  the  artery  the  flow  is  very  rapid  and  in  spurts,  in  the 
capillaries  it  is  many  times  slower  and  generally  moves  in  a  steady 


THE    HEART.  47 

stream.  In  the  veins  the  rapidity  of  the  now  increases  as  the 
blood  nears  the  heart,  but  moves  in  a  steady  stream,  and  does  not 
attain  the  speed  of  the  blood  in  the  arteries. 

What  is  the  pulse  ? 

The  pulse  is  caused  by  a  wave  of  force  which  travels  along 
the  column  of  blood  in  an  artery  as  a  direct  result  of  a  single 
contraction  of  the  heart;  in  other  words,  each  pulse  represents 
a  heart  beat,  but  not  the  blood  thrown  out  at  that  beat.  The 
stroke  given  by  the  heart  in  propelling  the  blood  onward  is 
expended  in  causing  not  only  the  forward  movement  of  the  whole 
mass  of  blood,  but  also  the  lateral  expansion  already  spoken  of. 
As  a  consequence  of  this,  each  pulse  is  like  an  expansion  wave, 
causing  the  vessel  to  expand  by  reason  of  the  increased  tension 
and  force  produced  by  the  heart  from  behind. 

Is  the  rapidity  of  the  pulse  wave  the  same  as  the  rapidity 
of  the  blood  stream  in  the  artery  ? 
No  ;  the  main  current  passes  along  the  vessel  at  a  given  rate  of 
speed,  while  the  force  of  each  systole  is  transmitted  along  the 
blood  stream  as  if  it  were  a  solid  piece  of  metal  or  wood,  which, 
having  been  struck  at  one  end,  transmits  a  wave  of  force  to  the 
other  end.  The  blood  being  enclosed  in  partially  rigid  walls 
carries  the  impulse  chiefly  forward,  not  laterally.  The  pulse  wave 
is  twenty  or  thirty  times  as  rapid  as  the  blood  current  its*  It. 

Does  the  pulse  cause  simply  a  lateral  dilatation  of  the 
bloodvessel? 
No  ;  the  bloodvessel  is  not  only  widened,  but  lengthened,  so  that 
a  straight  artery  may  he  seen  not  only  to  dilate,  but  also  to  become 
curved  to  make  up  for  its  elongation. 

Is  the  pulse  wave  equally  strong  in  all  portions  of  the 
body  ? 
No;  it  diminishes  in  force  and  in  speed  as  it  travels  onward,  due 
to  the  force  expended  in  distending  successive  parts  of  the  blood- 
vessel, friction,  and  other  causes.  As  a  consequence  of  this  the 
pulse  in  certain  portions  of  the  body  occurs  an  appreciable  l< 
of  time  after  the  cardiac  contraction  which  has  produced  it.    This 


48         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

is  noticed  particularly  in  the  radial  artery,  or  markedly  in  the  dor- 
salis  pedis  artery.  The  delay,  however,  even  at  the  most  distant 
point  amounts  to  not  more  than  one-sixth  to  one-eighth  of  a  second. 

At  what  speed  does  the  Wood  circulate  ? 

About  ten  metres  or  thirty-five  feet  per  second,  and  takes  but 
one-third  of  a  second  to  pass  a  given  point.  The  length  of  each 
pulse  wave  is,  therefore,  about  three  metres  (9J  feet),  or  twice  the 
length  of  the  longest  artery.  When  the  last  part  of  the  pulse 
wave  has  passed  the  arch  of  the  aorta  the  first  part  has  just  reached 
the  arterioles. 

RESPIRATION. 

The  respiratory  apparatus  is  divided  into  the  larynx,  trachea, 
bronchial  tubes,  bronchioles,  and  vesicles  in  the  lung.  Surround- 
ing each  lung  are  the  pleurae,  one  layer  of  which  is  attached  to  the 
lung  (visceral  layer),  the  other  to  the  chest  wall  (parietal  layer). 

What  is  the  object  of  respiration  ? 

In  order  to  bring  the  oxygen  of  the  air  in  close  relationship 
with  the  haemoglobin  in  the  blood,  and  to  permit  of  the  elimination 
of  C02  from  the  body,  as  well  as  other  effete  products  in  very 
minute  amount.  The  enlargement  of  the  chest  occurs  with  inspi- 
ration, the  contraction  of  the  chest  with  expiration. 

How  many  varieties  of  blood-supply  exist  in  the  lung  ? 

Two;  the  pulmonary  artery  supply,  and  the  bronchial  artery 
supply. 

What  is  the  function  of  these  two  varieties  ? 

The  pulmonary  artery  supplies  the  blood  for  aeration,  the 
bronchial  artery  that  for  the  nourishment  of  the  lung-tissue  itself. 

In  what  manner  is  the  blood  brought  to  the  vesicles  and 

exposed  to  the  air  ? 

The  smaller  branches  of  the  pulmonary  artery  split  up  more 

and  more,  and  have  the  peculiarity  that  they  do  not  anastomose  with 

one  another.   The  fine  capillaries  run  between  the  air  vesicles,  the 


RESPIRATION.  49 

thin  wall  of  the  vessel  and  vesicle  permitting  the  free  interchange 
of  gases  to  take  place. 

What  difference  do  we    have  in  the  distribution  of  the 
bronchial  and  pulmonary  veins  from  that  of  the 
arteries  ? 
The  pulmonary  and  bronchial  veins  anastomose  with  one  another. 
Is  the  circulation  more  or  less  rapid  in  the  lung  capillaries 
than  elsewhere? 
More  rapid,  since  their  area  is  not  so  great. 

Why  are  the  pulmonary  veins  slightly  smaller  than  the  artery? 
On  account  of  the  lessening  of  fluid  due  to  exhalation  of  moist- 
ure in  respiration. 

Are  the  movements  of  the  lung  passive  or  active  ? 

They  are  passive,  merely  following  the  movements  of  the  chest 
walls. 

What  are  the  movements  of  inspiration  ? 

In  inspiration  all  the  diameters  of  the  thorax  are  increased. 
The  lateral  or  transverse  diameter  is  increased  by  the  raising  of 
the  ribs ;  the  shape  of  the  ribs  and  their  relation  to  the  vertebral 
column  are  such  as  to  carry  them  outward  at  the  same  time  that 
they  are  raised.  This  same  movement  carries  the  sternum  for- 
ward, thus  increasing  the  antero-posterior  diameter.  The  increase 
in  the  vertical  diameter  is  due  to  descent  of  the  diaphragm,  the 
dome-shaped  surface  of  which  becomes  less  arched.  For  this 
reason  the  diaphragm  is  the  most  important  respirator//  muscle. 

The  other  muscles  concerned  in  the  inspiratory  act  are  the 
quadrati  lumborum,  serrati  postici  inferiores,  scaleni,  serrati  pos- 
tici  superiores,  levatores  costarum  longi  et  breves,  and  intereos- 
tales  externi  et  intercartilaginei. 

In  forced  inspiration  the  following  muscles  supplement  them : 
sterno-cleido-mastoidei,  trapezii,  pectorales  minores,  pectorales  ma- 
jores  (costal  portion),  thromboidei,  and  erectores  spina?. 
What  are  the  movements  of  expiration  ? 

Ordinary  expiration  is  a  passive  act,  brought  about  by  the  elastic 
tension  of  the  lungs,  costal  cartilages,  abdominal  viscera,  and  ab- 
dominal walls,  aided  by  the  weight  of  the  thorax.  Contraction  of 
the  intercostales  interni  interossei  may  assist.    In  forced  expiration 

4 


50         ESSENTIALS    OF     HUMAN     PHYSIOLOGY. 

these  muscles  are  active,  as  are  also  the  triangulares  sterni,  mus- 
culi  abdominales,  and  levatores  ani. 

What  effect  has  sex  on  respiration  ? 

In  men  respiration  is  largely  abdominal  or  diaphragmatic;  in 
women  chiefly  costal  or  thoracic.  These  differences  are  not  due  to 
sex,  but  to  dress  and  heredity.  In  young  children  respiration  is 
chiefly  diaphragmatic. 

Which  is  longer,  inspiration  or  expiration  ? 

The  mean  ratio  of  inspiration  to  expiration  is  as  5  :  6. 

What  sounds  do  we  hear  on  listening  to  the  chest  ? 

The  respiratory  murmurs,  which  are  produced  by  the  passage  of 
the  air  in  and  out  of  the  respiratory  apparatus. 

What  do  you  mean  by  "tidal  air"? 

The  ordinary  volume  of  air  respired,  amounting  to  about  thirty 
cubic  inches  in  the  adult. 

What  do  you  mean  by  "reserve  air"? 

The  air  which  can  be  voluntarily  emitted  after  ordinary  expira- 
tion.    It  amounts  to  about  one  hundred  cubic  inches. 

What  do  you  mean  by  " complemental  air"? 

The  amount  which  can  be  taken  in  after  an  ordinary  inspiration. 

What  do  you  mean  by  "residual  air"? 

It  is  the  amount  which  remains  after  forced  expiration,  equalling 
about  one  hundred  and  twenty  cubic  inches. 

What  does  the  term  "vital  capacity"  mean? 

The  greatest  amount  of  air  which  can  be  emitted  after  forced 
inspiration,  and  is  therefore  the  sum  total  of  reserve,  tidal,  and 
complemental  air.  It  varies  with  age,  sex,  size,  posture,  and  oc- 
cupation. The  total  quantity  in  an  adult,  passing  in  and  out  in 
twenty-four  hours,  is  686,000  cubic  inches;  in  hard-working  labor- 
ers, 1,568,390  cubic  inches.  For  every  inch  of  height  above  five 
feet  one  inch  the  capacity  should  increase  eight  cubic  inches. 

What  influence  has  sex  on  capacity  ? 

Females  have  less  capacity  than  males  where  the  chest  has  the 
same  circumference. 


RESPIRATION.  51 

How  many  respirations  a  minute  ? 
Fourteen  to  twenty,  but  the  number  is  influenced  by  Bex,  the 

age,  and  position,  also  by  exertion.  Thesi/.e  ot'tbe  animal  governs 
rapidity.  The  mouse  breathes  very  rapidly;  the  elephant  only 
eight  times  per  minute. 

What  effect  has  the  law  of  the  diffusion  of  gases  on  res- 
piration ? 
In  the  vessels  we  have  a  large  amount  of  C02,  while  in  the  air 
we  breathe  we  have  an  excess  of  O.  According  to  this  law,  there- 
lore,  the  0  attempts  to  get  in  as  the  CO,  attempts  to  get  out.  This 
law  also  prevents  the  reserve  and  residual  air  from  becoming  laden 
with  ( _'< ).,.  The  change  is  assisted,  too,  by  the  different  temperatures 
of  the  air  within  and  without. 

What  amount  of  work  is  performed  by  the  respiratory 
muscles  ? 

The  work  done  by  the  respiratory  muscles  is  estimated  by 
Haughton  at  21  foot-tons  in  twenty-four  hours. 

What  changes  have  we  produced  in  the  atmospheric  air 
by  respiration? 

1.  Increase  in  its  temperature. 

2.  Increase  in  C02. 

3.  Increase  in  organic  matter  and  free  ammonia. 

4.  Increase  in  watery  vapor. 

5.  Diminished  amount  of  O. 

The  expired  air  is  hotter  than  the  inspired  as  a  general  rule, 
but  on  a  hot  day,  with  the  atmosphere  al>ove  <k.s°  1'.,  it  is  cooler. 

The  temperature  varies  from  97°-99^.  1\.  according  to  the 
length  of  time  the  air  remains  in  the  lungs. 

Is  the  amount  of  CO.  exhaled  constant? 

It  varies  at  all  hours  of  the  day,  and  is  influenced  by  many  con- 
ditions. The  C02  given  off  by  a  normal  man  in  an  hour  equals 
1346  cubic  inches,  or  636  grains.  Accordingly  we  have  173  grains 
of  carbon  given  off  in  an  hour,  or  8  ounces  in  twenty-four  hours. 

Time  of  day,  varieties  of  food,  and  exercise,  greatly  influence 
the  amount  of  (.'( >.,. 


52         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

Does  age  affect  the  amount  of  COJ 

Yes ;  C02  increases  in  amount  from  8  to  32  years,  while  from 
35  to  50  it  remains  stationary,  or  slightly  falls.  After  50  years  it 
constantly  diminishes.  At  80  years  it  scarcely  exceeds  that  of  a 
child  of  10  years. 

How  much  0  is  abstracted  from  every  volume  of  air  ? 

About  4\  per  cent, 

What  effect  has  quickening  of  the  respiratory  movements 
on  the  amount  of  C02? 

The  quicker  the  respirations  the  less  C02  in  each  respiration, 
but  the  aggregate  amount  is  increased. 

What  portion  of  the  expired  air  contains  the  most  C02? 

That  of  the  last  half  of  expiration. 

What  effect  has  the  condition  of  the  atmosphere  on  the 
amount  of  C02? 

More  C02  is  given  off  when  air  is  moist  than  when  it  is  dry. 

What  influence  has  the  time  of  day  on  the  relative  amounts 
of  C02  and  0  ? 

During  the  day  more  C0.2  is  exhaled  than  O  is  taken  in;  while 
at  night  the  reverse  is  the  case.  In  other  words,  there  is  a  reserve 
fund  of  O  stored  up  at  night  to  meet  the  exigencies  of  the  day. 

Is  a  very  large  amount  of  watery  vapor  given  off  by  the 
lungs  ? 
Yes ;  almost  enough  to  saturate  the  expired  air.     The  amount 
equals  6  to  27  ounces  in  twenty-four  hours.     The  average  amount 
is  from  0  to  10  ounces. 

Does   ammonia  exist  as  a  physiological  constituent  of  all 
expired  air? 

No;  it  does  not.  It  is  chiefly  derived  from  decomposition  pro- 
ducts in  the  mouth. 


RESPIRATION.  53 

The  Nervous  Mechanism  of  Respiration. 

Is  respiration  purely  an  involuntary  act  ? 

No,  it  is  not;  since  we  can  "hold  the  breath,''  or  breathe  rapidly 
or  slowly,  superficially  or  deeply,  as  we  choose.  That  it  is  in- 
voluntary to  a  great  extent  is  proved  by  the  fact  that  one  does  not 
stop  breathing  when  asleep  or  unconscious. 

Respiration  is  governed  by  a  centre,  the  respiratory  centre,  in 
the  medulla  oblongata  near  the  calamus  scriptorius. 

What  keeps  this  centre  active  ? 

It  is  kept  active  by  the  condition  of  the  blood.  If  the  amount 
of  O  is  too  small  the  centre  sends  out  impulses  and  increases 
respiration. 

Describe  this  centre  more  fully. 

There  is  a  respiratory  centre  on  each  side  of  the  medulla 
oblongata,  and  these  may  in  turn  be  divided  into  two  centres, 
namely,  the  greater  one  for  inspiration  and  lesser  for  expiration. 

Does  the  expiratory  centre  constantly  send  out  impulses  ? 

\<>;  it  is  only  active  on  rare  occasions,  as  when  there  is  some 
obstruction  to  respiration. 

Are  there  any  centres  for  respiration  higher  up  in  the 
nervous  system  than  the  medulla  oblongata  ? 
No.  All  phenomena  which  have  suggested  such  a  centre  can 
easily  be  explained  as  centripetal  stimulations  of  the  medulla 
oblongata,  which  hy  reflex  action  act  on  the  respiratory  centre  in 
the  fourth  ventricle. 

Are  there  any  respiratory  centres  in  the  cervical  part  of 
the  cord  ? 
No.     Only  the  tracts  which  carry  the  impulses. 

What  do  you  mean  by  eupnoea,  apncea,  and  dyspnoea  ? 

Eupncea  is  normal  breathing;  apncea  is  a  condition  in  which  too 
much  O  is  absorbed  into  the  blood,  and  is  readily  produced  by 
forced  artificial  respiration.  Remember,  that  the  use  of  the  word 
apncea  to  indicate  a  condition  in  which  breathing  has  ceased  froir. 
the  ordinary  causes,  is  incorrect.    Breathing  in  apnoea  ceases  from 


54        ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

the  excess,  not  the  lack,  of  oxygen.     Dyspnoea  is  labored  or  diffi- 
cult breathing. 

What  effect  has  the  pneumogastric  apparatus  on  respi- 
ration ? 
If  both  vagi  are  cut  the  respirations  become  somewhat  deep  and 
full.     If  these  nerves  are  stimulated  the  respirations  become  very 
rapid  and  violent. 

Is  this  change  due  to  a  direct  transmission  of  the  stimulus 
along  the  nerves  to  the  lungs,  or  to  a  reflex  wave 
to  the  respiratory  centre  ? 

It  is  due  to  a  reflex  wave  to  the  respiratory  centre.  Remember, 
that  the  vagus  nerves  are  made  up  of  both  efferent  and  afferent 
fibres.  Also  remember,  that  not  only  do  we  have  an  efferent  and 
afferent  set  of  fibres,  but  that  the  afferent  fibres  are  made  up  them- 
selves of  two  sets  of  fibres,  one  of  which,  the  central  end  of  the 
superior  laryngeal  branch,  after  it  has  been  cut,  when  stimulated 
slows  the  respirations,  while  stimulation  of  the  central  end  of  the 
vagus  itself  quickens  the  respirations.  When  the  nerve  is  stimu- 
lated the  impulse  goes  upward  to  the  centre,  and  from  there  is 
irradiated  down  to  the  organs. 

Si<jhing  is  a  long  inspiration.  When  great  attention  is  being 
paid  we  speak  of  "  shallow  breathing."  In  other  words,  we  almost 
forget  to  breathe.  Sighing  always  follows  this  condition,  and 
makes  up  for  the  shallow  breathing  before  it. 

Hiccough  is  a  sudden  inspiration  due  to  descent  of  the  diaphragm. 

Coughing  is  expiratory. 

Sneezing  is  expiratory,  but  is  preceded  by  a  full  inspiration. 

In  speaking  we  expire. 

Sobbing  consists  of  a  series  of  short  inspirations,  after  each  of 
which  the  glottis  is  closed. 

Laughing  is  a  series  of  short  and  rapid  expirations. 

DIGESTION. 

What  three  forms  of  digestion  have  we  ? 
Salivary,  gastric,  and  intestinal. 


DIGESTION.  55 

What  is  the  function  of  salivary  digestion  ? 

To  convert  starch  into  maltose. 
On  what  does  the  gastric  digestion  act  ? 

( )n  the  proteids,  converting  them  into  peptones. 

What  part  of  digestion  is  carried  on  in  the  small  intestine  ? 

The  fats  art'  prepared  for  absorption  by  being  emulsified,  the 
proteids  converted  into  peptones,  and  starch  is  changed  to  maltose 
and  dextrose 

The  salivary  secretion  is  derived  from  what  three  glands  ? 

The  submaxillary,  sublingual,  and  parotid.  The  mucous  glands 
present  in  the  mouth  are  solely  for  the  purpose  of  lubrication. 

Describe  the  characteristics  of  the  saliva. 

It  is  a  mixture  of  the  secretion  of  the  three  glands  named,  and 
is  a  slightly  turbid,  tasteless  fluid  of  a  distinctly  alkaline  reaction. 
The  specific  gravity  is  1003.  It  contains  five-tenths  per  cent,  of 
solids,  the  greater  part  of  which  are  organic,  such  as  mucin,  which 
produces  the  viscidity,  traces  of  albumin,  and  a  peculiar  ferment, 
ptyalin.  The  inorganic  constituents  are  salts,  the  chief  one  of 
which  is  potassium  sulphocyanide,  which  may  be  readily  per- 
ceived by  its  odor  when  saliva  is  kept  for  a  short  time  in  a  test 
tube.  The  other  portions  of  the  saliva  are  made  up  of  salivary 
corpuscles  which  contain  nuclei,  and  are  probably  altered  leuco- 
cytes, epithelial  cells,  and  various  microorganisms. 

How  much  saliva  is  secreted  in  twenty-four  hours  ? 
From  7  to  70  ounces. 

What  is  the  difference  between  parotid  saliva  and  that  of  the 
other  glands  ? 
It  contains  more  ptyalin,  a  smaller  amount  of  urea,  traces  of 
a  volatile  acid,  and  some  inorganic  constituents,  as  >alts  of  soda 
and  potash  ;  it  contains  no  mucin,  and  is  much  thinner  than  is  the 
secretion  of  the  submaxillary  or  sublingual  glands. 

Describe  the  submaxillary  saliva. 

Submaxillary  saliva  is  markedly  alkaline,  tenacious,  and  con- 
tains mucin;  it  contains  much  less  ptyalin  than  does  parotid 
saliva. 


56         ESSENTIALS    OF    HUMAN     PHYSIOLOGY. 

Describe  the  sublingual  saliva. 

Sublingual  saliva  is  more  sticky  and  cohesive  than  either  of  the 
others,  and  contains  much  mucin,  salivary  corpuscles,  and  potas- 
sium sulphocyanide. 

What  is  the  nerve  supply  of  the  salivary  glands  ? 

The  submaxillary  glands  are  supplied  by  the  chorda  tympani, 
which  is  derived  from  the  facial  nerve.  It  also  receives  filaments 
from  the  superior  cervical  ganglion  of  the  sympathetic,  and  from 
the  submaxillary  ganglion. 

Remember,  that  the  chorda  tympani  contains  two  sets  of  fibres: 
1st,  true  secretory  fibres  ;  2d,  vaso-dilator  fibres. 

The  sympathetic  also  contains  two  sets  of  fibres :  1st,  true  secre- 
tory ;  2d,  vaso-constrictor  fibres. 

The  sublingual  glands  are  supplied  by  the  same  nerves  as  supply 
the  submaxillary.  The  parotid  glands  are  supplied  by  branches  of 
the  facial  which  join  the  auriculo-temporal  branches  of  the  fifth 
pair  of  cranial  nerves. 

What  is  the  effect  of  section  of  the  chorda  tympani  ? 

The  flow  of  saliva  is  very  greatly  decreased. 

What  is  the  effect  of  stimulation? 

Increased  salivary  flow  and  increased  glandular  vascularity. 

What  is  the  effect  of  stimulation  of  the  facial  nerve  at  its 
origin  in  the  floor  of  the  fourth  ventricle  ? 
It  increases  the  salivary  flow  from  the  submaxillary  gland. 

What  is  the  effect  of  stimulation  of  the  sympathetic  ? 

It  causes  a  decrease  in  the  salivary  flow,  with  contraction  of  the 
bloodvessels  and  consequent  decrease  in  vascularity. 

Does  the  increase  in  salivary  flow  depend  upon  increased 
vascularity  ? 
No ;  since  if  all  the  bloodvessels  going  to  the  gland  be  tied,  secre- 
tion is  still  increased  either  when  the  chorda  tympani  is  stimulated 
or  when  the  sympathetic  is  paralyzed  ;  under  these  circumstances 
the  extra  liquid  required  is  obtained  from  the  lymph  vessels  and 
spaces.  Atropine  and  daturine  are  drugs  which  decrease  salivary 
secretion  by  depressing  the  chorda  tympani  peripherally. 


DIGESTION.  57 

Remember,  that  mere  increase  in  vascularity  in  the  salivary  glands 
does  not  of  necessity  increase  the  flow  of  saliva.  The  only  influence 
which  increased  vascularity  exerts  is  a  greater  supply  of  liquid 
which  escapes  from  the  gland  rather  by  leakage  than  by  secretion. 

Is  the  pressure  in  the  excretory  ducts  of  the  salivary  glands 

very  great  ? 

Yes  ;  Ludwig  has  found  that  the  pressure  in  these  ducts  may  be 

twice  as  great  as  the  blood-pressure  in  the  carotid  itself.     The 

pressure  in  Wharton's  duct  may  equal  200  millimetres  of  mercury. 

What  is  the  cause  of  the  great  pressure  in  the  salivary 
ducts? 
It  is  due  to  the  secreting  power  of  the  cells  in  the  gland. 

What  change  in  temperature  occurs  in  the  gland  ? 

During  secretion  the  temperature  of  the  gland  rises,  so  that  it  is 
often  warmer  than  the  arterial  blood. 

How    do    you    produce  increased    salivary  flow  from  the 
parotid  1 

By  stimulation  of  the  facial  nerve  after  it  has  joined  the  auriculo- 
temporal branch  of  the  fifth  or  trifacial  nerve,  or  reflexly  by  stimu- 
lation of  the  glosso-pharyngeal  nerve. 

In  what  way  is  secretion  brought  about  when  food  enters 
the  mouth? 
Reflexly  through  the  lingual  branch  of  the  glosso-pharyngeal 
and  the  inferior  maxillary  branch  of  the  trifacial  or  fifth  nerve, 
which  carry  the  impulses  up  to  the  centre  in  the  medulla. 

What  effect  has  section  of  the  chorda  tympani  on  this 
reflex  ? 
If  the  chorda  tympani  be  cut  previous  to  the  introduction  of  a 
substance  into  the  mouth  no  increase  of  flow  comes  from  the  glands 
which  it  supplies;  but  if  the  sympathetic  be  cut  the  reflex,  although 
partially  interfered  with,  is  not  prevented. 

Is  the  rate  of  secretion  always  the  same  ? 

No ;  it  varies  according  to  the  condition  of  the  mouth  and  the 
food  in  it. 

What  effect  have  the  movements  of  mastication  on    the 
salivary  flow  ? 
They  increase  it. 


58  ESSENTIALS    OF     HUMAN    PHYSIOLOGY. 

In   what   condition   is    an    increased   flow    of    saliva   pro- 
duced? 
When  nausea  is  present,  profuse  salivary  secretion  occurs  by  a 
reflex  through  the  vagus  nerve. 

What  is  the  physiological  action  of  saliva  ? 

Its  most  important  action  is  its  diastatic  or  amylolylic  action,  or, 
in  other  words,  the  transformation  of  starch  into  dextrins,  and  of 
dextrins  into  maltose. 

What  do  you  mean  by  the  term  diastatic  ? 

The  power  which  certain  substances  have  of  acting  on  starch 
and  converting  it  into  sugar. 

Upon  what  does  the  diastatic  power  of  saliva  depend  ? 

Upon  ptyalin . 

Is  the  ptyalin  destroyed  when  it  acts  ? 

Scarcely  at  all,  for  it  acts  by  catalysis,  or  its  mere  presence. 

What  effect  have  high  and  low  temperatures  on  the  action 
of  ptyalin? 
High  and  low  temperatures  prevent  its  action,  and  boiling  and 
freezing  stop  it  absolutely. 

What  is  the  sugar  called  which  is  formed  by  the  action  of 
the  saliva  ? 
The  sugar  formed  by  the  action  of  saliva  on  starch  is  called 
maltose,  which  is  converted  into  dextrose  by  an  inverting  enzyme 
in  the  small  intestine.  It  is  in  the  form  of  dextrose,  or  dextrose 
and  levulose,  that  the  carbo-hydrates  are  absorbed. 

What  is  the  object  of  boiling  starchy  foods  ? 

In  order  to  break  up  the  cellulose  coverings  of  the  starch  gran- 
ules, and  enable  the  diastatic  ferment  to  attack  the  starch. 

What  is  the  first  change  in  the  starch  as  it  is  digested  ? 
It  becomes  liquefied. 

What  are  the  mechanical  uses  of  saliva  ? 

It  keeps  the  mouth  moist,  facilitates  speaking  and  the  mastica- 
tion of  food,  also  the  movements  of  the  tongue.  It  dissolves 
certain  substances,  and  renders  them  capable  of  being  tasted ;  by 


DIGESTION.  59 

mixing  with  food  it  forms  a  soft  bolus  which  is  easily  swallowed 
and  digested. 

What  are  movements  of  mastication  ? 

1.  The  elevation  of  the  jaw  is  accomplished  by  the  combined 
action  of  the  temporal,  masseter,  and  internal  pterygoid  muscles. 

2.  The  depression  of  the  jaw  by  its  own  weight,  aided  by  the 
action  of  the  anterior  bellies  of  the  digastrics,  mylohyoids  and 
genio-hyoids,  and  the  platysmas. 

3.  The  displacement  of  the  articular  surfaces  backward  or  for- 
ward is  produced,  when  forward,  by  the  external  pterygoid  muscles 
which  pull  the  jaw  down  and  forward.  As  one  external  pterygoid 
acts  it  pulls  the  jaw  sideways  and  we  have  a  grinding  movement. 
When  the  movement  is  backward  the  digastric  and  hyoid  muscles 
act. 

What  is  the  function  of  mastication  ? 

We  divide,  by  this  means,  the  food  into  small  pieces,  biting  it 
off  by  the  incisors,  tearing  it  off  by  the  canines,  and  grinding  it 
up  by  the  molars.  Soft  food  is  broken  up  by  the  tongue  pressing 
it  against  the  roof  of  the  mouth.  By  this  means  the  digestive 
fluids  may  attack  the  food  more  readily. 

What  is  the  function  of  the  tongue  in  mastication? 

To  keep  the  food  between  the  teeth,  in  which  it  is  assisted  by 
the  muscles  of  the  lips  and  the  buccinator  muscles. 

In  what  way  is  deglutition  accomplished  ? 

1.  The  aperture  of  the  mouth  is  closed  by  the  orbicularis  oris. 

2.  The  jaws  are  pressed  together  by  the  muscles  of  mastication. 

3.  The  tip,  middle,  and  root  of  the  tongue,  one  after  the  other, 
are  pressed  against  the  hard  palate,  thereby  propelling  the  food 
backward.  Just  at  this  time  the  levator  palati  draws  the  soft  palate 
upward  and  backward,  completely  closes  the  posterior  openings  oi 
the  nasal  cavities,  and  the  intrinsic  muscles  of  the  larynx  firmly 
close  the  rirna  glottidis. 

4.  After  the  anterior  palatine  arch  is  passed,  it  is  prevented  from 
returning  to  the  mouth  by  the  palato-glossi  muscles,  lying  in  the 
anterior  pillars  of  the  fauces. 

5.  The  bolus  is  now  urged  on,  first,  by  the  action  of  the  superior 
constrictors  of  the  pharynx,  next  the  middle,  and  third  the  inferior 
constrictors. 


60         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

6.  Having  reached  the  cesophagus,  it  is  urged  on  by  the  outer 
longitudinal  and  the  inner  circular  non-striped  muscular  fibres, 
which  contract  peristaltically.  Recent  experiments  show  that  this 
peristalsis  only  occurs  on  forced  deglutition,  the  food  ordinarily 
being  projected  into  the  oesopbagus  by  the  voluntary  muscles. 

What  is  the  nervous  mechanism  of  deglutition  ? 

The  centre  for  swallowing  is  in  the  medulla  oblongata.  The 
efferent  nerves  which  govern  deglutition  are :  the  hypo-glossal, 
which  supplies  the  hyoid  or  tongue  muscles ;  the  glosso-pharyngeal 
and  vagus  nerves  to  the  pharyngeal  plexus,  which  supply  the  con- 
strictor muscles;  and  the  facial  and  fifth,  which  supply  the  fauces 
and  palate.  The  movements  of  the  cesophagus  are  governed  both 
afferently  and  efferently  by  the  vagus,  which  also  acts  with  the 
superior  maxillary  branch  of  the  trifacial.  The  afferent  vagus 
filaments  for  the  first  part  of  deglutition  are  the  pharyngeal 
branches  of  the  anterior  laryngeal  branches. 

The  Stomach. 

What  varieties  of  cells  do  we  find  in  the  stomach  ? 

In  the  cardiac  end  of  the  stomach  we  have  two  distinct  kinds 
of  cells.  One  kind,  the  most  numerous,  consists  of  small,  pale, 
spheroidal  cells  which  line  the  interior  of  the  glands.  The  other 
cells  are  much  fewer  as  well  as  larger,  and  are  scattered  over  the 
fundus  of  the  glands. 

What  two  sets  of  glands  have  we  in  the  stomach  ? 

The  mucous,  which  are  chiefly  situated  at  the  pyloric  end  of  the 
stomach,  and  those  which  secrete  gastric  juice. 

What  are  the  movements  of  the  stomach  ? 

When  the  stomach  is  empty  it  lies  with  its  greater  curvature 
downward  and  its  lesser  upward ;  when  it  is  full  the  greater  cur- 
vature swings  forward  against  the  abdominal  wall,  while  the  lesser 
curvature  approximates  itself  to  the  spinal  column. 

What  other  gastric  movements  have  we? 

We  have  two  distinct  varieties  of  gastric  movement  different 
from  the  two  mentioned  :  the  first  is  a  rotatory  or  churning  move- 
ment whereby  the  walls  glide  over  the  food,  these  movements  occur 
periodically  and  last  for  several  minutes,  their  function  is  to 
moisten  the  food  by  the  gastric  juice  and  break  it  up ;  the  other  is 


DIGESTION. 


61 


Fig.  4. 


Diagram  of  a  section  of  the  wall  of  stomach,     o,  orifices  of  gland*,  with  cylindrical 
epithelium,     b,  fundus  of  glands,  wirh  spherical  and  oval  epithelium,     c,  muscularis 

mucosae,     d,  submucous  tissue,  containing  bl (vessels,  etc.    e,  circular  ;  /,  oblique,  and 

g,  longitudinal  muscle  coats,    ft,  serous  membrane. 

Fig   5. 


• 


Mi 


Diagram  showing  the  relation  of  the  ultimate  twigs  of  the  bloodvessels  (V  and  A)  and 
of  the  absorbent  radicals  (L)  to  the  glands  of  the  stomach,  and  the  different  kinds  of 

epithelium,  viz.:  above  cylindrical  cells;  small,  pale  cells  in  the  lumen  ;  outside  of  which 
are  the  dark  ovoid  cells.     (Yeo.) 


62         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

the  peristaltic  movement  whereby  the  food  is  pushed  out  into  the 
duodenum  through  the  pylorus. 

What  are  the  intrinsic  and  extrinsic  nerves  of  the  stomach  ? 
Auerbach's  plexus  is  the  motor  portion  of  the  apparatus.     The 
left  vagus  supplies  the  anterior  surface  of  the  stomach,  the  right 
vagus  supplies  the  posterior  surface. 

Describe  the  gastric  juice. 

It  is  a  tolerably  clear,  colorless  fluid  (straw-colored),  of  acid  reac- 
tion, sour  taste,  and  peculiar  characteristic  odor;  it  is  not  rendered 
turbid  by  boiling  and  resists  putrefaction  for  a  long  time;  its  spe- 
cific gravity  is  1002.5.  The  quantity  secreted  in  twenty-four  hours 
amounts  to  from  eight  to  fourteen  pints. 

What  does  the  gastric  juice  contain? 

First,  pepsin,  the  characteristic  nitrogenous  hydrolytic  ferment, 
which  dissolves  proteids;  second,  hydrochloric  acid,  the  chief  acid 
present;  also  small  amounts  of  lactic  acid.  The  latter,  however,  is 
not  secreted,  but  is  due  to  decomposition  of  carbo-hydrates  in  the 
stomach. 

Which  cells  secrete  the  greatest  amount  of  pepsin? 
Those  at  the  cardiac  end  of  the  stomach. 

Does  pepsin  exist  in  the  glands  ready  formed? 

According  to  most  physiologists  it  is  due  to  the  presence  of  a 
compound  known  as  pepsinogen,  which  forms  pepsin  as  soon  as 
it  comes  in  contact  with  hydrochloric  acid  in  the  stomach. 

What  is  the  function  of  lactic  acid  ? 

It  digests  the  proteids  in  much  the  same  manner  as  does  hydro- 
chloric acid. 

Does  secretion  go  on  constantly  in  the  stomach  ? 
No.     Only  on  the  entrance  of  stimuli,  such  as  food,  etc. 

What  change  takes  place  in  the  gastric  mucous  membrane 
on  the  entrance  of  food  ? 

It  becomes  red  and  the  circulation  more  active. 

What  happens  to  the  gastric  juice  when  the  food  passes 
out  of  the  stomach  into  the  alkaline  intestine  ? 
It  is  neutralized  and  part  of  the  pepsin  reabsorbed. 


DIGESTION.  63 

What  is  chyme  ? 

The  mixture  of  food  and  gastric  juice. 

What  effect  has  gastric  juice  upon  proteids  ? 

It  changes  the  proteids  first  into  a  substance  known  as  syntonic 
or  acid-albumin,  which  is  immediately  changed  again  into  pro- 
peptone  or  hemi-albuminose  or  para-peptone.  The  para-peptone 
h  now  converted  into  peptone,  which  is  absorbed  into  the  blood 
from  the  small  intestine  and  immediately  converted  back  again 
into  proteids,  and  so  deposited  in  the  tissues. 

Does  pepsin  suffer  any  change  when  acting  ? 
It  acts  chiefly  by  catalysis,  but  is  partially  destroyed. 
(For  properties  of  peptones  and  para-peptones,  see  page  19.) 

Is  any  albumin  absorbed  unchanged  ? 

According  to  Yeo,  a  considerable  quantity  of  albumin  is  absorbed 
unchanged,  both  from  the  stomach  and  intestines. 

What  other  special  ferment  have  we  in  the  stomach? 
The  milk-curdling  ferment. 

What  is  the  action  of  the  gastric  juice  on  carbo-hydrates? 

It  has  no  effect  on  starch,  inulin,  or  the  gums.  Cane-sugar  is 
slowly  changed  by  it  into  dextrose  and  levulose. 

Why  does  not  the  stomach  digest  itself? 

There  is  much  discussion  in  regard  to  this  point.  Xo  satisfac- 
tory explanation  has  been  given.  Some  physiologists  teach  that 
the  protection  which  the  coats  of  the  stomach,  during  life,  seem  to 
have  is  due  to  the  constantly  circulating  alkaline  blood  through 
them. 

This  explanation  is  unsatisfactory,  as  it  does  not  explain  why 
the  small  intestine  is  not  digested  by  its  alkaline  fluids.  All  that 
can  be  said  in  either  case  is  that  living  tissue  is  protected  from 
self-digestion  by  the  properties  of  its  living  structure. 

What  gases  have  we  in  the  stomach  ? 

Those  which  are  derived  from  the  air  which  is  swallowed  with 
the  saliva  and  those  which  regurgitate  from  the  duodenum.  Besides 
these  we  have  gases  which  arise  in  eases  of  dyspepsia  from  fermen- 
tative and  putrefactive  changes  in  the  food. 


64         ESSENTIALS    OF    HUMAN    PHYSIOLOGY". 

What  is  the  mechanism  of  vomiting  ? 

It  is  caused  by  contraction  of  the  walls  of  the  stomach,  whereby 
the  pyloric  sphincters  are  closed.  It  occurs  most  easily  when  the 
stomach  is  distended,  and  in  infants,  owing  to  the  peculiarity  of  the 
position  of  their  stomachs,  the  regurgitations  of  milk  are  due  to 
scarcely  more  than  reverse  d  peristalsis.  In  children,  therefore,  the 
abdominal  muscles  do  not  always  aid  in  the  expulsion  of  food.  In 
adults  they  always  do. 

In  what  way  is  vomiting  produced  ? 

Vomiting  is  produced  either  by  an  action  on  the  peripheral  ends 
of  the  nerves  of  the  stomach  or  by  direct  action  on  the  vomiting 
centre  in  the  medulla. 

What  effect  has  section  of  the  vagi  on  vomiting  ? 
It  prevents  it. 

Do  we  ever  have  bile  in  vomit  ? 

Frequently  when  the  vomiting  is  so  severe  as  to  cause  the  bile 
to  flow  out  of  the  duodenum  into  the  stomach. 

What  is  the  movement  called  by  which  food  is  passed 
along  through  the  intestines  ? 

Peristalsis. 

In  what  portion  of  the  intestinal  tract  is  peristalsis  most 
marked  ? 

In  the  small  intestine. 

What  is  peristalsis  ? 

Peristalsis  is  the  constantly  moving  onward  of  a  contractile  wave 
along  the  wall  of  the  gut,  or,  in  other  words,  is  the  progressive 
narrowing  of  the  tube  from  above  downward. 

Do  the  movements  of  the  stomach  and  intestine  continue 

during  sleep  ? 

Some  physiologists  believe  that  they  do ;  others  that  they  do 
not.  The  matter  is  largely  one  of  opinion,  but  it  is  probable  that 
the  first  opinion  is  the  correct  one. 


DIGESTION.  65 

What  do  you  mean  by  reversed  peristalsis  ? 

A  condition  in  which  the  peristaltic  wave  travels  from  below 
upward,  the  cause  of  which  has  been  supposed  by  sonic  to  be  due 
to  the  fact  that  one  band  of  the  muscular  fibres  in  the  gut  misses 
a  contraction. 

What  are  the  functions  of  the  muscular  coat  of  the  intes- 
tine ? 
To  carry  on  peristalsis. 

What  nervous  influence  is  exercised  over  intestinal  move- 
ments ? 
Auerbach's  plexus  is  the  automatic  motor  centre  which  lies 
between  the  muscular  coats  and  produces  peristaltic  movements 
iu  sections  of  the  gut  removed  from  the  body.  Meissner's  plexus 
is  much  less  important,  supplying  only  a  few  motor  fibres  to  the 
muscular  coats,  and  a  few  motor  and  sensory  fibres  to  the  muscularis, 
mucosa?,  and  intestinal  glands. 

What  do  you  mean  by  aperistalsis  ? 

An  absolute  abolition  of  peristaltic  movement.  Normal  peris- 
talsis is  known  as  euperistalsis.  When  peristalsis  becomes  very 
violent  it  is  known  as  dy aperistalsis. 

What  influence  has  the  circulation  of  the  blood  on  peri- 
stalsis ? 
Violent  peristaltic  movement  is  produced  by  interrupting  the 
circulation  of  blood  in  the  wall  of  the  gut,  whether  the  stoppage  is 
due  to  congestion  or  anaemia  of  the  parts.  This  is  the  cause  of  the 
marked  peristalsis  preceding  death. 

What  are  the  inhibitory  nerves  of  the  gut  ? 

The  splanchnics,  which,  however,  also  contain  motor  filaments. 

What  effect  has  stimulation  of  the  splanchnics  on  peri- 
stalsis ? 
If  the  blood  supply  is  normal  it  slows  or  prevents  them.  If 
abnormal,  it  increases  them.  The  reason  of  this  is  that  the  inhibi- 
tory fibres  of  the  splanchnics  are  paralyzed  by  venous  blood  in  the 
gut,  but  the  motor  fibres  are  not. 


66 


ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 


Pancreatic  Digestion. 

Describe  the  pancreas. 

The  pancreas  is  a  large  racemose  gland  attached  by  its  lateral 
branchlets  to  its  main  central  duct.  The  cells  making  up  the 
gland  may  be  divided  into  two  zones,  an  external  homogeneous 
zone  and  an  internal  granular  zone.  Each  zone  corresponds  to 
one-half  of  tbe  cells,  the  clear  half  being  next  tbe  boundary,  and 
the  granular  half  being  next  the  lumen  of  the  saccule. 

Fig.  6. 


a.  B. 

One  saccule  of  the  pancreas  of  the  rabbit  in  different  states  of  activity.  A.  After  a 
period  of  rest,  in  which  case  the  outlines  of  the  cells  are  indistinct,  and  the  inner  zone  — 
i.e.,  the  part  of  the  cells  (a)  next  the  lumen  (c) — is  broad  and  filled  with  fine  granules 
B.  After  the  gland  has  poured  out  its  secretion,  when  the  cell  outlines  (d)  are  clearer, 
the  granular  zone  (a)  is  smaller,  and  the  clear  outer  zone  is  wider.     (Kuhne  and  Lea.) 

Describe  the  pancreatic  juice. 

Pancreatic  juice  is  thick,  transparent,  odorless,  and  saltish  in 
taste.  The  saltish  taste  is  due  to  the  presence  of  sodium  carbonate ; 
if  acid  be  added  C02  is  liberated.  It  acts  powerfully  as  a  digestive 
airent. 


What  is  the  appearance  of  the  pancreas  when  at  rest  and 
at  work  ? 

During  digestion  it  is  red  and  turbid,  and  at  other  times  pale 
and  anaemic. 


DIGESTION.  67 

What  is  the  function  of  the  pancreatic  juice  ? 

It  contains  at  least  four  hydrolytic  ferments,  and  is,  therefore,  a 
most  important  digestive  fluid. 

What  are  these  four  pancreatic  ferments  ? 

(1)  The  diastatle  action  is  caused  by  a  ferment  known  as  amylop- 
x'ni,  a  substance  wbich  seems  to  be  identical  with  the  ptyalin  of 
the  saliva. 

What  is  the  difference  between  the  action  of  this  ferment 
and  ptyalin  on  starch  ? 

It  is  much  more  powerful  than  ptyalin. 

(2)  The  tryptic  action,  which  is  caused  by  the  presence  of  a  sub- 
stance known  as  trypsin,  or  pancreatin,  which  acts  on  proteids 
converting  tbem  into  peptones,  or,  as  they  are  sometimes  called, 
tryptones.  Tbe  intermediary  product  between  a  proteid  and  a 
tryptone  is  alkali-albumin,  corresponding  to  the  acid-albumin  of 
gastric  digestion. 

What  are  leucin  and  tyrosin  ? 

Substances  normally  found  in  the  small  intestine  produced  by  a 
too  prolonged  action  of  trypsin  on  its  self-formed  peptone.  They 
are  crystallizable  nitrogenous  bodies. 

What  are  skatol  and  indol  ? 

Strong,  stinking  decomposition  products  resulting  from  the  con- 
tinuation, pathologically,  of  this  action  of  trypsin  on  peptone. 

What  is  the  difference  in  the  manner  in  which  trypsin  acts 
on  albuminous  matters  from  that  of  the  gastric 
juice? 

In  gastric  digestion  fibres  of  meat  swell  up  before  they  are 
dissolved.  In  pancreatic  digestion  they  do  not  swell  up  but 
become  eroded. 


68         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  reaction  is  necessarily  present  for  the  pancreatic 
action  to  take  place  ? 

An  alkaline  reaction. 

What  is  the  alkali  commonly  present  ? 

Sodium  carbonate,  the  presence  of  which  is  as  necessary  to  tlr 
pancreatic  action  as  hydrochloric  acid  is  to  the  pepcic  action. 

What  two  forms  of  tryptones  have  we? 

One  known  as  anti-peptone,  the  other  as  hemi-peptone. 

What  is  the  action  of  the  pancreatic  juice  on  fats  ? 

It  first  forms  them  into  a  fine  emulsion,  and  secondly  causes 
them  to  take  up  a  molecule  of  water  and  split  up  into  glycerine 
and  fatty  acids.  This  action  of  the  pancreatic  juice  is  due  to  the 
third  ferment,  known  as  steapsin. 

According  to  Kiihne  and  Roberts  the  pancreas  contains,  fourth, 
a  milk-curdling  ferment.  The  four  are,  therefore,  as  follows :  ainy- 
lopsin,  trypsin,  steapsin,  and  the  milk-curdling  ferment. 

At  what  time  is  the  pancreatic  juice  poured  out  ? 

On  the  entrance  of  food  into  the  small  intestine  coming  from 
the  stomach. 


THE  LIVER. 

The  anatomy  of  the  liver  is  so  closely  concerned  in  its  physio- 
logical functions  that  an  outline  seems  unnecessary  at  this  point.  It 
will  be  remembered  that  the  liver  is  made  up  of  many  little  livers 
known  as  lobes  and  lobules,  each  lobule  being  a  perfect  gland  in 
itseif.  The  bloodvessels  are  derived  from  two  sources,  first,  the 
venous,  which  enter  by  means  of  the  vena  porta;  and  which,  branch- 


THE    LIVER, 


69 


ing,  give  off  numerous  interlobular  vessels  or  veins  forming  dense 
plexuses  around  the  lobules.  Branching  off  from  these  interlobular 
vessels  are  the  capillaries  which  converge  to  the  centre  of  the 
lobule,  forming  elongated  meshes,  between  which  are  rows  of  cells. 


Section  of  lobule  of  liver  of  rabbit  in  which  the  blood  and  bile  capillaries  hav^'  been 
Injected  (after  Cadiat).  a.  Intralobular  vein.  b.  Interlobular  veins,  c.  Biliary 
sanaJa  beginning  in  fine  capillaries. 


These  capillaries  on  reaching  the  centre  of  the  lobule  form  the 
intralobular  vessel  or  central  vein,  which  again  joins  together  with 


70 


ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 


others  and  forms  the  radicles  of  the  hepatic  veins.  The  second  set 
of  bloodvessels  are  branches  of  the  hepatic  artery  which  dip  down 
between  the  lobules  to  nourish  the  whole  gland  tissue  whatever  it 
may  be.  The  third  set  of  vessels  which  are  present  are  known  as 
the  bile-ducts,  which,  arising  from  the  centre  of  the  lobule  join 
one  another  and  form  the  interlobular  bile  ducts,  which  anastomose 
and  finally  form  the  common  biliary  duct. 


Fig.  8. 


J^# 


Section  of  the  liver  of  the  newt,  in  which  the  bile  ducts  have  been  injected,  and  can 
be  seen  to  form  a  network  of  fine  capillaries  around  the  liver  cells,  the  outlines  and 
nuclei  of  which  can  be  seen. 


What  is  the  chemical  composition  of  the  liver  cells  ? 

First,  proteids  or  albuminous  matters.  Second,  glycogen,  or 
animal  starch,  which  is  a  true  carbo-hydrate,  and  is  changed  into 
sugar  by  a  diastatic  ferment. 

What  conditions  influence  the  quantity  of  glycogen  ? 

The  eating  of  large  quantities  of  starch,  milk,  fruit,  or  cane-sugar 
increases  it  greatly,  while  purely  albuminous  or  fatty  diets  decrease 
it  greatly. 

What  are  the  sources  of  glycogen  ? 

It  is  probably  derived  from  the  carbo-hydrates  of  the  food. 


THE    LIVER.  71 

What  are  the  functions  of  the  liver  ? 

The  functions  of  the  liver  are  three — the  secretion  of  bile,  the 
formation  of  glycogen,  and  the  destruction  of  worn-out  blood  cells. 

What  is  the  use  of  glycogen  in  the  body  ? 
It  is  not  really  known. 

Describe  the  bile. 

Bile  is  a  yellowish-brown  or  dark  green  transparent  fluid  with  a 
neutral  reaction  and  a  bitter  taste.  Its  specific  gravity  is  from  1010 
to  1050. 

What  does  bile  contain  ? 

First,  mucus,  which  makes  it  viscid,  and  which  comes  from  the 
walls  of  the  gall-bladder.  Second,  the  bile  acids,  glyco-cholic  and 
tauro-cholic  acids,  which  unite  with  soda,  forming  cholates. 

Which  of  the  bile  acids  occur  in  human  bile  ? 

Both  are  usually  present,  though  tauro-cholic  may  be  absent. 

What  is  Pettenkofer's  test  for  bile  ? 

Add  concentrated  H2S04  drop  by  drop,  then  add  a  ten  per  cent, 
solution  of  cane-sugar  when  a  reddish  purple  color  is  struck. 

What  is  Heintz's  test  ? 

Heintz's  test  consists  in  adding  nitric  acid,  when  a  play  of  colors 
results. 

What  are  the  bile  pigments  ? 

Bilirubin,  which  is  yellowish-brown  ;  biliverdin,  which  is  green ; 
bilifuscin,  biliprasin,  and  hydro-bilirubin,  the  last  being  the  normal 
coloring  matter  of  the  feces. 

What  is  cholestrin  ? 

Cholesterin  is  an  univalent  alcohol  which  occurs  ill  the  yolk  of 
eggs,  and  in  solution  in  the  bile. 

Is  the  secretion  of  bile  a  mere  filtration  of  substances  already 
in  the  blood  ? 
No;  it  is  a  true  secretion,  being  produced  by  the  cells  of  the 
glauds. 


72         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  is  the  quantity  of  bile  secreted  per  day  ? 

About  seventeen  ounces. 

What  is  the  difference  between  the  contents  of  the  blood- 
stream in  the  hepatic  vein  and  the  portal  vein  ? 

The  hepatic  vein  contains  more  sugar  (?),  cholesterin,  and  blood- 
corpuscles,  and  less  albumin,  fibrin,  free  haemoglobin,  fats,  water, 
and  salts. 

In  what  way  is  the  coloring  matter  of  the  bile  obtained  ? 

By  destruction  of  worn-out  blood  corpuscles. 

What  are  the  functions  of  the  bile  ? 

The  emulsification  of  the  fats,  the  lubrication  of  the  walls  of  the 
intestine,  and  to  increase  the  osmotic  power  of  the  wall  of  the  gut 
in  order  to  facilitate  the  absorption  of  fats.  It  also  prevents  to  a 
very  considerable  extent  decomposition  and  stimulates  peristahc 
action. 

What  is  the  fate  of  bile  in  the  intestine  ? 

►Sorne  of  it  passes  out  with  the  feces,  and  part  is  absorbed  and 
eliminated  as  urobilin.  The  cholesterin  is  given  off  with  the  feces, 
and  the  bile  salts  are  for  the  most  part  reabsorbed  by  the  gut. 

Have  the  other  juices  of  the  small  intestine  any  digestive 
power  ? 

They  probably  have  some  power  in  the  solution  of  the  proteids, 
and  perhaps  a  diastatic  action. 

What  is  the  fate  of  the  salivary,  gastric,  and  pancreatic 
ferments  ? 
Ptyalin  is  destroyed  in  the  stomach  by  the  acid  pepsin,  and  the 
milk-curdling  ferment  by  the  alkaline  salts  of  the  pancreatic  and 
intestinal  juices  and  by  trypsin,  the  diastatic  ferment  of  the  pan- 
creas by  acid  fermentation  in  the  large  intestine. 

What  is  the  function  of  the  large  intestine  ? 

It  absorbs  the  liquids  from  the  fecal  matter  .coming  from  the 
small  intestine. 

What  is  the  amount  of  feces  in  twenty-four  hours  ? 
Six  to  twenty  ounces  according  to  the  character  of  the  food. 


ABSORPTION. 


73 


ABSORPTION. 

Fig.  9. 


Diagram  showingthe  course  of  the  main  trunks  of  the  absorbent  system.     The  lym- 
phatlcBof  lower  extremities,  etc.,  meeting  the  lacteals  of  intestines  at  the  receptaculum 

chyli  (R.  C  ),  which  opens  into  the  thoracic  duct.  The  superficial  vessels  are  Bhown  in 
the  diagram  on  the  left  arm  and  leg  (S),  and  the  deeper  oues  on  the  arm  to  the  right  f  D). 
The  glands  are  here  and  there  shown  in  groups.  The  small  right  duct  opens  int.)  the 
veins  on  the  right  side.  The  thoracic  duct  discharges  into  the  union  of  the  great  reins 
of  the  left  side  of  the  neck.     (Yeo.) 

Tlie  mucous  membrane  of  the  whole  alimentary  canal  is  capable  of 
absorption,  some  portions  more  so  tha?i  others. 

Describe  the  intestinal  mucous  membrane. 

In  the  mucous  membrane  are  found  small  glands  of  two  kinds — 
the  first  are  Brunner's  glands,  and  are  localized  in  the  duodenum, 
the  others  are  those  of  Lieberkiihn,  which  are  distributed  over  the 
entire  intestinal  tract  in  great  numbers. 


74 


ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 


What  is  a  villus  ? 

A  small  process  from  the  wall  of  the  intestine,  containing  blood- 
vessels and  a  lacteal. 

In  what  two  ways  does  absorption  occur  ? 
By  means  of  the  blood-capillaries  and  the  lacteals. 

What  substances  are  absorbed  by  the  capillaries  and  what 
by  the  lacteals  ? 
The  first  absorbs  sugars  and  proteids,  the  lacteals  the  fats. 

Fig.  10. 


Drawing  of  transverse  section  of  duodenum,  showing  Brunner's  glands  (B)  opening 
into  Lieberkuhn's  follicles  (L);  V,  villi;  M,  muscular  coats.     (Yeo.) 

What  portion  of  the  gastro-intestinal  tract  carries  on  the 
greatest  amount  of  absorption? 
The  upper  half  of  the  small  intestine. 

What  is  the  position  of  the  lacteal  ? 

It  lies  in  the  axis  of  the  villus,  and  is  surrounded  by  a  blood- 
vessel and  a  vein.  The  lacteals  anastomose  in  the  sub-adenoid 
tissue  of  the  gut,  and  finally  form  lymphatic  networks  which 
end  in  the  receptaculum  chyli,  the  beginning  of  the  thoracic 
duct  which  opens  into  the  subclavian  vein  on  the  left  side  near 
the  junction  of  the  jugular.  The  villi  are  possessed  of  unstriped 
muscular  fibres,  which  aid  in  emptying  the  lacteal,  and  the  nerves 
which  supply  them  are  derived  from  Meissner's  plexus. 

What  three  forces  are  at  work  in  the  absorption  of  digested 
food? 

Endosmosis,  diffusion,  and  filtration. 


ABSORPTION. 


75 


What  do  you  mean  by  endosmosis  and  diffusion  ? 

Endosinosis  is  the  change  which  occurs  between  two  fluids  which 
are  capable  of  forming  an  intimate  mixture  with  each  other  through 
an  animal  membrane,  but  never  between  two  fluids  which  do  not 

Fig.  11. 


Villus,  with  capillaries  injected,  showing  their  close  relation  to  epithelium,  some  of  the 
cells  <>f  which  axe  distended  with  mucus.    (Cadiat.) 

form  a  perfect  mixture,  such  as  oil  and  water.  Diffusion  is  tin- 
mixing  of  two  liquids  placed  one  over  the  other  in  a  vessel  without 
the  presence  of  a  septum. 

What  is  the  law  in  regard  to  the  diffusion  of  crystalloids 
and  colloids? 
Crystalloids  will  diffuse  into  colloids,  but  colloids  will  not  diffuse 


76  ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

into  crystalloids.  Filtration  occurs  in  the  small  intestine  simply 
by  the  pressure  which  is  exerted  upon  the  fluid  by  the  contraction 
of  the  walls,  and  also  by  a  negative  pressure  or  suction  produced 
by  the  villi. 

What  is  the  influence  of  the  nervous  system  on  absorption  ? 

Our  knowledge  is  limited,  but  it  has  been  found  that  after  extir- 
pation of  the  semilunar  ganglion  of  Budge,  or  section  of  the  mesen- 
teric nerves,  the  intestinal  contents  became  very  fluid,  which  may 
be  due  to  diminished  absortion. 


ANIMAL    HEAT. 

What  do  you  mean  by  the  term  animal  heat? 

The  temperature  at  which  the  body  of  a  warm-blooded  animal 
is  maintained. 

What  is  the  normal  temperature  of  man  ? 
98f  °  F. 

Is  it  constant  in  all  persons  ? 

It  varies  but  a  fraction  of  a  degree. 

Do  all  animals  have  the  same  temperature  as  man  ? 

No  ;  birds  have  as  high  as  107°  F.,  and  dogs  as  high  a  tempera- 
ture as  103°  F.  In  the  lower  animals  the  bodily  temperature  of 
members  of  the  same  species  often  varies. 

Upon  what  does  the  temperature  of  cold-blooded  animals 
depend  ? 
Upon  the  temperature  of  the  surrounding  medium. 

What  conditions  influence  bodily  temperature  ? 

Age,  sex,  period  of  day,  exercise,  climate  and  season ;  food  and 
drink  also  influence  it. 

What  is  the  effect  of  age  ? 

The  temperature  of  a  newborn  child  is  one  degree  above  that 
proper  to  the  adult.  In  full  adult  life  the  temperature  is  lower 
than  at  any  other  time  since  it  rises  again  iu  old  age. 


ANIMAL    HEAT.  77 

What  effect  has  the  period  of  day? 

The  variation  may  equal  one  to  one  and  a  half  degrees,  the  mini- 
mum late  at  night  or  early  in  the  morning;  the  maximum  late  in 
die  afternoon. 

What  is  the  effect  of  exercise  ? 

It  raises  the  temperature;  but  physiologists  differ  as  to  the  actual 
amount  of  increase  thus,  some  state  that  the  rise  of  temperature 
produced  by  exercise  never  raises  the  general  bodily  temperature 
more  than  about  1°  F.,  while  others  believe  that  it  raises  it  much 
more.  Those  who  think  the  actual  general  rise  is  slight,  believe 
that  the  great  rise  occurring  in  tetanus,  where  all  the  muscles  con- 
tract, is  due  to  some  other  concomitant  pathological  condition. 
Students  must  be  governed  in  regard  to  this  point  by  the  opinion 
of  their  instructor.  Climate  and  season  have  very  slight  influence 
over  the  bodily  temperature. 

What  variations  in  bodily  temperature  may  we  have  in 
disease  ? 

In  fever  we  may  have  a  temperature  as  high  as  106°  and  110°, 
or  even  11")    F.    In  Asiatic  cholera  it  sometimes  falls  to  77°  or  79°. 

What  difference  is  there  in  the  temperature  of  different 
portions  of  the  body  ? 

The  surfaces  of  the  hands  and  feet  are  cooler  than  any  other 
portion  of  the  body,  while  the  liver  often  is  as  high  as  105°  F. 

From  what  source  is  animal  heat  derived  ? 

The  ultimate  source  is  contained  in  the  potential  energy  taken 
into  the  body  with  food  and  with  the  oxygen  during  respiration," 
but  the  amount  of  heat  formed  depends  upon  the  amount  of  kinetic 
energy  liberated.  The  energy  of  the  food  stuffs  may  be  called 
"latent  heat."  (For  definitions  of  these  terms,  see  Bodily  Me- 
tabolism.) 

What  are  the  direct  sources  of  heat  ? 

The  blood  during  digestion  becomes  laden  with  more  carbon, 
hydrogen,  and  oxygen  than  is  needful  for  the  repair  of  the  ,:- 
and  these  gases  uniting  with  the  sulphates  develop  heat  by  chemi 


78         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

cal  means  very  rapidly,  while  the  rest  of  the  heat  of  the  body  i 
more  slowly  developed  by  a  slower  combustion.     The  brain,  the 
muscles,  and  the  glands  manufacture  heat,  so  that  venous  blood 
leaving  one  of  these  parts  is  warmer  than  arterial  blood. 

Is  there  any  difference  in  the  heat-producing  properties  of 
different  food  stuffs  ? 
Fat  are  particularly  heating,  giving  more  kinetic  energy. 

What  is  the  nervous  mechanism  of  animal  heat  ? 

In  the  brain  is  seated  a  heat  centre  whose  function  it  is  to  direct 
the  rapidity  of  combustion  or  the  development  of  heat  in  the  body. 
Governing  this  centre  are  two  others,  the  inhibitory  heat  centre 
(Wood),  whose  function  it  is  to  prevent  a  too  rapid  production  of 
heat,  and  the  accelerator  heat  centres  (Sachs  and  Aronsohn),  whose 
function  it  is  to  increase  the  production  of  heat. 

What  two  functions  govern  the  temperature  of  the  body? 

Heat  production  and  heat  dissipation.  Heat  production  consists 
in  the  manufacture  of  a  certain  number  of  heat  units  or  calories  in 
a  given  space  of  time  in  the  body,  while  heat  dissipation  is  the 
function  by  which  a  certain  number  of  heat  units  are  given  off 
from  the  body  to  the  surrounding  atmosphere  or  medium. 

What  is  the  effect  of  increased  heat  production  and  de- 
creased dissipation? 
Increase  in  temperature,  or,  in  other  words,  fever. 

What  is  the  effect  of  a  decrease  in  heat  production  or  an 
increase  in  heat  dissipation  ? 
A  fall   of  temperature.     Remember  that  these  two   functions 
balance  one  another  and  that  disorder  of  either  of  them  either 
raises  or  lowers  bodily  temperature. 

Under  what  circumstances  is  the  dissipation  of  heat  in- 
creased ? 
By  cold  surroundings,  by  conditions  which  bring  large  quan- 
tities of  heat  to  the  surface  of  the  body,  and  by  contact  of  the  body 
with  substances  which  readily  conduct  the  heat  away. 


ANIMAL    HEAT.  79 

What  keeps  the  temperature  of  the  body  uniform  ? 

The  circulation  of  the  blood,  which  distributes  the  heat  very 
evenly. 

What  conditions  of  the   vasomotor  system  influence  the 
distribution  of  heat  ? 
Local  dilatations  of  the  bloodvessels  produce  increased  tempera- 
ture of  the  part  and  increased  heat  dissipation,  and,  indirectly, 
increased  local  heat  production. 

What  is   the  function  of  the  perspiration  in  regard  to 
bodily  heat  ? 
By  its  evaporation  it  aids  enormously  in  the  dissipation  of  heat 
when  heat  is  formed  in  or  added  to  the  body  too  rapidly. 

Why  can  a  person  stand  a  high  heat  in  a  dry  atmosphere 
better  than  in  a  moist  atmosphere  ? 
Because  in  a  dry  atmosphere  the  perspiration  is  evaporated  so 
rapidly  that  the  heat  is  readily  dissipated. 

How  high  a  temperature  may  the  human  being  stand  in 
an  absolutely  dry  atmosphere  ? 
According  to  Blagden,  a  temperature  of  198°  to  211°  F.  was 
supported  in  dry  air  for  several  moments,  and  on  one  occasion  he 
stood  260°  F.  for  eight  minutes,  having  trained  his  skin  to  exces- 
sive secretion.  Workmen  in  English  iron  furnaces  sometimes 
stand  on  a  furnace  floor  which  is  red  hot  and  the  air  of  which 
stands  at  350°  F.  Chabert,  the  so-called  "fire-king,"  is  said  to 
have  stood  from  400°  to  600°  F.,  according  to  Morrant  Baker. 

Which  one  of  the  animal  tissues  is  the  best  protector 
against  cold? 

The  fatty  layer,  which  nearly  always  occurs  in  varying  amounts 
under  the  skin  in  all  warm-blooded  animals,  and  forms  a  protective 
covering  whereby  the  conduction  of  internal  heat  is  almost  im- 
possible. 

Fibrous  tissues  conduct  heat  more  readily  in  the  direction  of 
their  fibres  than  at  right  angles.  The  bones  are  the  next  best  con- 
ductors of  heat,  and  are  followed  by  blood-clots.    The  spleen,  liver, 


80         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

cartilage,  tendon,  muscle  and  elastic  tissue,  and  nails  follow  as 
conductors  of  heat.     The  skin  is  a  poor  conductor  of  heat. 

What  influence  has  starvation  on  the  bodily  temperature  1 

It  lowers  it  greatly. 

What  effect  has  sleep  and  hemorrhage  on  temperature  ? 

In  those  persons  who  sleep  during  the  day  and  work  at  night 
the  typical  course  of  the  temperature  is  inverted  from  that  which 
has  been  already  stated  as  normal.  Hemorrhage  causes  at  first  a 
slight  fall  in  temperature,  and  after  that  a  rise  of  several  tenths  of 
a  degree,  which  is  curiously  usually  associated  with  a  chill  or  slight 
rigor.     Several  days  after  this  the  temperature  falls  again. 

What  is  the  cause  of  the  fall  of  temperature  after  hemor- 
rhage ? 
The  interference  with  oxidation. 

What  effect  has  the  artificial  cooling  of  animals  ? 

It  produces  great  depression,  but  voluntary  and  reflex  movements 
are  not  abolished.  The  pulse  falls  from  100  to  150  to  20  beats  per 
minute,  the  blood  pressure  falls,  the  respirations  become  shallow, 
and  death  occurs  with  spasms  and  signs  of  asphyxia. 

What  is  the  asphyxia  due  to  ? 

Failure  of  respiration :  for  if  artificial  respiration  be  employed 
at  this  time  the  temperature  rises  fifteen  to  twenty  degrees.  Lan- 
dois  asserted  that  if  in  addition  to  artificial  respiration  external 
warmth  be  applied,  animals  apparently  dead  for  forty  minutes  can 
be  resuscitated. 

What  is  hibernation  ? 

A  condition  in  which  an  animal  has  all  its  vital  processes 
temporarily  in  abeyance.  Respiratory  and  intestinal  movements 
cease  completely  and  the  cardio-pneumatic  movements  alone 
sustain  the  slight  exchange  of  oxygen  in  the  lungs.  If  a  warm- 
blooded animal  be  cooled  to  30°  F.,  it  wakes  before  freezing. 
Varnishing  the  skin  of  an  animal  increases  heat  dissipation  so 
enormously  that  death  occurs,  which  is  put  aside  if  external  heat 
be  applied. 


THE    KIDNEYS.  81 


THE    KIDNEYS. 

What  are  the  kidneys? 
Compound  tubular  glands. 

What  is  the  function  of  the  kidneys  ? 
Their  function  is  the  secretion  of  urine. 

What  is  the  purpose  of  the  large  amount  of  fat  around 
these  organs? 
It  acts  as  a  protective. 

What  is  the  size  of  the  adult  kidney  ? 

About  four  and  four-tenths  of  an  inch  long,  three  inches  thick, 
and  two  inches  wide.  In  the  male  it  weighs  from  four  to  six  ounces, 
in  the  female  from  four  to  five  and  a  half  ounces. 

Of  what  two  portions  is  the  kidney  made  up  ? 

The  parenchyma,  consisting  of  the  outer  or  cortical  layer,  and 
the  inner  or  medullary  layer.  The  medullary  layer  is  also  some- 
times called  the  pyramidal  portion. 

Into  what  two  divisions  is  the  medullary  portion  divided? 
It  is  subdivided  into  the  boundary  layer  of  Ludwig  and  the 
papillary  portion. 

What  appearance  has  the  cortical  portion  of  the  kidney 
when  torn  ? 
It  presents  a  granular  aspect,  due  to  the  presence  of  the  Mal- 
pighian  corpuscles.    Striae  are  also  seen,  due  to  the  medullary  rays. 

What  is  the  difference  between  the  boundary  zone  or  layer 

of  Ludwig,  and  the  papillary  portion  of  the  kidney  ? 

The  boundary  zone  is  darker,  and  often  purplish  in  color,  while 

the  papillary  zone  is  nearly  white,  and  uniformly  striated.     The 

stria?  merge  into  the  apex  of  the  pyramid. 

Which  is  the  least  pliable,  the  cortex  or  medullary  portion? 
The  medulla  of  the  kidney  is  less  pliable  than  the  cortex.    This 

6 


82 


ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 


is  due  to  the  greater  amount  of  connective  tissue,  and  the  bundles 

of  straight  tubes  which  may  be  traced  at  regular  intervals,  running 

upward,  and  becoming  smaller  and  smaller  as  they  pass  toward 

the  periphery. 

Fig.  12. 


Longitudinal  section  through  the  kidney  (after  Tyson  and  Henle).  1.  Cortex.  1'. 
Medullary  rays.  1".  Labyrinth.  2.  Medulla.  2'.  Papillary  portion  of  medulla.  2". 
Boundary  layer  of  medulla.  3.  Transverse  section  of  tubules  in  the  boundary  layer. 
4.  Fat  of  renal  sinus.  5.  Artery.  *  Transverse  medullary  rays.  A.  Branch  of  renal 
artery.     C.  Renal  calyx.     U    Ureter. 

In  what  portion  of  the  kidney  is  the  labyrinth  ? 

That  portion  of  the  cortex  which  occurs  between  the  medullary 
rays  is  called  the  labyrinth,  owing  to  the  arrangement  of  its  tubules. 


THE    KIDNEYS.  83 

How  many  pyramids  have  we  in  each  kidney  ? 

Usually  about  eight  or  twelve.  The  pyramids  are  sometimes 
called  those  of  Malpighi  or  Ferrein.  The  apices  of  the  pyramids 
are  directed  toward  the  pelvis  of  the  kidney,  while  their  bases 
are  directed  toward  the  cortex,  and  each  one  of  them  opens  into 
a  small  saccule  or  calyx,  which  in  turn  forms  with  others  a  dilated 
pouch,  situated  at  the  pelvis  of  the  kidney,  forming  the  beginning 
of  the  ureter. 

How  many  times  do  we  have  the   pelvis  of  the  kidney 
divided  ? 
First,  into  two  or  three  divisions,  and  then  again  into  eight  or 
twelve  smaller  ones,  which  are  called  calyces. 

What  is  the  function  of  a  calyx  ? 

It  receives  the  point  of  one  pyramid,  generally,  but  sometimes 
two  pyramids  empty  into  one  calyx. 

What  do  you  mean  by  the  tubuli  uriniferi  ? 

Fine,  very  elongated  tubes,  composed  of  a  nearly  homogeneous 
membrane,  and  lined  by  epithelium  possessing  the  power  of  secre- 
tion. These  tubes  are,  on  the  average,  one  six-hundredth  of  an 
inch  in  diameter.  They  begin  at  the  Malpighian  corpuscle  in  the 
cortical  portion  of  the  kidney,  and,  after  passing  through  many 
convolutions,  finally  end  in  the  pyramidal  bodies,  from  the  papilla- 
like point  of  which  the  urine  drops  into  the  saccules  already  men- 
tioned. 

In   what    portion    of  the    kidney   do   we  find  the  tubuli 
uriniferi  ? 
Both  in  the  medullary  and  cortical  portions. 

Into  how  many  divisions  are  they  divided? 
Fifteen. 

Is  there  any  difference  in  the  function  of  each  division  ? 
Certain  sections  are  supposed  to  secrete  certain  substances. 

What  is  the  glomerulus  or  Malpighian  body  ? 

It  is  composed  of  a  small  tuft  of  bloodvessels  covered  with  a 


84        ESSENTIALS    OF    HUMAN     PHYSIOLOGY. 

layer  of  cells  and  surrounded  by  a  membranous  covering,  known 
as  Bowman's  capsule,  which  is  the  beginning  or  dilated  extremity 

Fig.  13. 


Inner  stratum  of  cortex,  without 
Malpighian  corpuscles. 


|e     without  Malpighian 


Subcapsular  layer 
without  Ms 
corpuscles. 


i  Cortex. 


Diagram  of  two  uriniferous  tubules.  (Tyson  and  Brunton,  after  Klein  and  Noble 
Smith.)  1.  Malpighian  tuft  surrounded  by  Bowman's  capsule.  2.  Constriction,  or  neck. 
3.  Proximal  convoluted  tubule.  4.  Spinal  tubule.  5.  Descending  limb  of  Henle's  loop. 
6.  Henle's  loop.  7  and  8.  Ascending  limb  of  Henle's  loop.  9.  Wavy  part  of  ascending 
limb  of  Henle's  loop.  10.  Irregular  tubule.  11.  Distal  convoluted  tubule.  12.  First 
part  of  collecting  tube.  13  and  14.  Straight  part  of  collecting  tube.  15.  Excretory 
ducts  of  Bellini. 

of  the  uriniferous  tubule.  They  are  apparent  to  the  naked  eye, 
in  the  cortical  portion  of  the  kidney,  as  little  red  points.  Their 
average  diameter  is  xjffth  of  an  inch. 

What  is  the    function  of  the  glomerulus   or  Malpighian 
tuft  or  corpuscles  ? 
According  to  most  physiologists,  the  Malpighian  tuft  secretes  the 


THE    KIDNEYS. 


85 


liquids  and  salts  of  the  urine,  while  the  epithelial  lining  of  the 
uriniferous  tubules  secretes  urea  and  uric  acid,  <>r  any  substance 
which  taken  into  the  body  is  eliminated  by  the  kidneys. 

Fig.  14. 


Bowman's  capsule  and  glomerulus  (after  Lanpoik).  a.  Vas  afferens.  e.  Tas  efferons. 
c.  Capillary  network  of  the  cortex,  k.  Endothelial  structure  of  the  capsule,  h.  Origin 
of  convoluted  tubule. 

What  peculiar  arrangement  have  we  in  the  blood  supply 
of  the  Malpighian  tuft  ? 

The  blood  passes,  by  means  of  the  afferent  vessel  or  artery,  to  the 
Malpighian  tuft  and  enters  it,  giving  off  immediately  a  capillary 
network.  At  the  other  side  of  this  capillary  network  a  vessel 
goes  off,  which,  as  a  general  rule,  does  not  leave  the  Malpighian 
body  on  the  opposite  side  from  the  entrance  of  the  artery,  but  finds 
its  exit  from  the  same  opening  as  that  by  which  the  artery  entered. 
The  uriniferous  tubule,  however,  is  given  off  from  the  Malpighian 
body  on  the  opposite  side  from  that  at  which  the  artery  enters 
and  the  efferent  vessel  leaves. 

The  capsule  of  Bowman,  or  the  beginning  of  the  uriniferous 
tubule,  may  be  considered  as  a  sac,  into  which  is  secreted  the  liquid 
by  the  Malpighian  tuft. 

Is  the  efferent  vessel  called  a  vein  ? 
The  efferent  vessel  after  leaving  the  Malpighian  body  forms  a 


86 


ESSENTIALS    OF    HUMAN    PHYSIOLOGY, 


second  capillary  network,  twisting  around  the  uriniferous  tubules. 
Not  until  these  capillaries  come  together  do  they  form  one  vessel, 
known  as  the  vein. 

Why  is  the  efferent  vessel  smaller  than  the  artery  ? 

It  is  somewhat  smaller  for  the  reason  that  it  loses  some  of  its 
liquid  in  the  Malpighian  body. 

What  other  vessels  have  we  ? 

Besides  the  efferent  and  afferent  vessels,  we  have  those  known  as 
the  vasa  recta,  which,  instead  of  being  concerned  in  any  way  with 
the  Malpighian  tufts,  pass  directly  out  of  the  kidney,  through  the 
medullary  portion. 

Fig.  15. 


Longitudinal  section  of  kidney  (after  Ludwio  and  Tyson)  PF.  Pyramids  of  Feivein. 
RA.  Rranch  of  renal  artery.  EV.  Lumen  of  renal  vein  receiving  an  interlobular  vein. 
VR.  Vasa  recta.  PA.  Apex  of  a  renal  papilla,  b,  b,  embrace  the  bases  of  the  renal 
lobules. 


THE    KIDNEYS.  87 

What  is  their  function  ? 

Their  function  is  to  afford  a  side  stream  for  the  blood  in  cases  of 
congestion,  so  that  all  of  it  will  not  of  necessity  pass  to  the  paren- 
chyma of  the  organ. 

What  other  vessels  carry  on  a  side  stream  ? 

Another  side  stream,  which  is  less  important,  but  for  the  same 
purpose,  is  produced  by  the  fine  interlobular  arteries  which,  as 
they  approach  the  surface  of  the  kidney,  communicate  with  the 
capillaries  of  the  external  capsule. 

In  what  way  is  the  kidney  nourished  ? 

By  bloodvessels  which  dip  down  from  the  capsule,  and  from  the 
vasa  recta. 

What  are  the  nerves  of  the  kidney  ? 

They  are  derived  from  the  renal  plexus  and  the  lesser  splanch- 
nics. 

Do  these  nerves  govern  secretion,  or  only  the  blood  supply? 
We  know  that  they  govern  blood  supply,  but  it  is  not  proven 
that  they  influence  secretion. 

What  effect  has  increased  blood  pressure  on  the  urinary 
secretion  ? 
According  to  most  of  the  text-books,  increased  blood  pressure 
increases  urinary  flow,  and  vice  versa;  but  recent  investigations 
have  seemed  to  prove  that  blood  pressure  has  no  very  great  influ- 
ence over  the  kidney.  The  urine  which  is  increased  by  pressure, 
contains  less  solids,  proportionately,  than  urine  formed  by  stimu- 
lation. "Pressure"  urine  is  scarcely  more  than  a  leakage,  and 
not  a  true  secretion. 

What  is  the  function  of  the  ureters  ? 

To  carry  the  urine  from  the  pelvis  of  each  kidney  to  the  bladder. 

Do  the  ureters  possess  any  power  of  urging  on  the  flow  ? 

Yes;  they  have  a  slight  peristaltic  movement,  and  are  supplied 
by  motor  and  sensory  nerves,  the  sensory  nerves  showing  their 
presence  in  the  human  being  when  a  calculus  is  being  passed. 


88         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

How  long  does  it  take  the  wave  of  contraction  to  travel 
along  the  ureters  from  the  kidney  to  the  bladder  ? 

About  one-tenth  of  a  second. 

In  what  way  do  the  ureters  enter  the  bladder  ? 

Obliquely.  They  enter  the  external  wall  of  the  bladder  at  one 
point,  pass  between  its  coats  for  a  short  distance,  and  then  open  on 
its  inner  surface. 

In  what  way  is  this  opening  arranged  ? 

A  small  papilla  with  a  valve-like  action,  permits  the  urine  to 
flow  out  but  not  to  return,  and  the  oblique  manner  in  which  the 
ureter  enters  the  bladder  forms  a  sharp  bend  in  that  tube  which 
acts  as  a  valve,  particularly  when  the  bladder  is  distended. 

What  mechanical  arrangement  have  we  to  prevent  leakage 
from  the  bladder  ? 

At  the  neck  of  the  bladder  the  circular  muscular  fibres  are 
strongly  developed,  and  act  as  a  sphincter,  and  in  addition  to  this 
is  the  muscle  known  as  the  sphincter  of  the  urethra,  which  also 
acts  in  very  much  the  same  way.  Remember!  Both  these  muscles 
must  relax  before  urination  can  take  place. 

What  is  the  function  of  the  bladder  ? 

To  retain  the  urine  until  a  sufficient  quantity  has  been  collected 
to  pass,  in  order  that  a  constant  dribble  may  not  take  place. 

What  is  its  capacity  ? 
About  one  pint. 

In  what  condition  is  the  mucous  membrane  of  the  bladder 
when  the  bladder  is  empty  ? 
It  is  thrown  into  rugous  folds. 

What  is  the  cause  of  the  movement  of  the  urine  ? 

First,  it  is  formed  under  high  pressure  in  the  kidney ;  second, 
gravity,  when  the  person  is  erect,  aids  its  passage;  and,  third, 
the  muscles  of  the  ureter  contract  rhythmically,  and  so  aid  its 
onward  flow.  This  movement  of  the  ureter  is  reflex,  and  is  due  to 
the  presence  of  the  urine  in  it. 


THE    KIDNEYS.  89 

Do  both  kidneys  act  constantly? 
No  ;  they  act  alternately. 

What  influence  has  the  ingestion  of  small  or  large  quanti, 
ties  of  water  on  the  urinary  flow  ? 
During  thirst  it  amounts  to  but  two  or  three  drops  every  minute, 
when  drinking  it  often  runs  in  a  steady  stream. 

In  what  way  is  the  urine  discharged  from  the  bladder  ? 

By  contraction  of  its  muscular  coats,  which,  it  will  be  remem- 
bered, run  in  all  directions. 

What  muscles  aid  in  the  voluntary  act  of  urination  ? 

The  respiratory  muscles  and  abdominal  muscles.  The  diaphragm 
is  fixed,  and  the  act  is  completed  by  the  accelerator  urinie  muscle, 
which  quickens  the  stream. 

In  what  portion  of  the  spinal  cord  is  the   centre  for  the 
bladder  ? 
In  the  lumbar  region. 

What  other  muscle  aids  in  the  expulsion  of  the  last  drops 
of  urine,  other  than  the  accelerator  urinae  ? 
The  bulbo-cavernosus. 

What  is  the  nervous  mechanism  of  urination  ? 

The  sphincter  vesicae  is  kept  in  a  state  of  contraction  by  the 
motor  centre  governing  it  in  the  cord. 

When  the  urine  collects  in  the  bladder  a  sensory  impulse  travels 
to  the  cord  and  brain,  and  the  brain  and  cord  in  turn  send  down 
motor  impulses  which  contract  the  muscular  walls  of  the  bladder, 
while  a  second  impulse  relaxes  the  sphincters. 

Where  is  the  spinal  centre  for  urination  situated? 

Al>out  the  point  of  origin  of  the  third,  fourth,  and  fifth  Bacral 
nerves. 


90         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 


THE  URINE. 

How  much  urine  is  secreted  in  twenty-four  hours  ? 
About  three  pints  in  the  normal  adult. 

At  what  time  of  the  day  does  the  minimum  secretion  take 
place? 
Between  2  and  4  A.  M. 

At  what  time  of  the  day  does  the  maximum  secretion  take 
place? 
Between  2  and  4  p.m. 

What  are  some  of  the  causes  that  diminish  the  quantity 
of  urine  ? 
It  is  diminished  by  increase  in  the  sweat,  diarrhoea,  thirst,  non- 
nitrogenous  food,  diminution  of  blood-pressure,  and  certain  dis- 
eases. 

What  are  the  causes  which  increase  its  quantity  ? 

It  is  increased  by  increased  blood-pressure,  by  copious  drinking, 
by  exposure  to  cold,  by  the  use  of  nitrogenous  food,  and  various 
conditions  of  the  nervous  system.  Various  drugs  also  influence 
the  quantity. 

What  is  the  specific  gravity  of  the  urine? 

It  varies  from  1.005  to  1.015  to  1.025.  The  minimum  specific 
gravity  occurs  after  copious  drinking  and  may  be  1.002 ;  the  maxi- 
mum after  profuse  sweating,  and  may  be  1.040.  The  mean  specific 
gravity  is  1.020. 

What  ready,  but  not  strictly  accurate,  method  have  we 

for  determining  the  amount  of  solids  in  a  given 

specimen  of  urine  ? 

By  the  use  of  Christison's  formula,  which  consists  in  multiplying 

the  last  two  figures  of  the  specific  gravity  by  2.33,  which  will  give 

the  amount  of  solids  in  one  thousand  cubic  centimetres. 


THE    URINE.  91 

What  is  the  color  of  the  urine  due  to  ? 

The  color  depends  on  the  matters  present  in  it,  chiefly  UTO- 
chronie  and  urobilin,  a  derivative  of  hematin.  The  color  varies 
greatly, but  the  difference  in  intensity  is  chiefly  governed  by  the 
quantity  of  water  which  is  present. 

What  is  the  cause  of  the  slight  cloudiness  which  appears 
in  the  bottom  of  a  vessel  in  which  urine  is  placed 
for  a  length  of  time  ? 
It  is  due  to  mucus,  which  is  chiefly  derived  from  the  bladder. 

What  is  the  taste  and  odor  of  urine  ? 

Its  taste  is  slightly  alkaline  or  bitter;  its  odor  characteristic  and 
aromatic.  The  odor,  however,  is  altered  by  various  causes,  par- 
ticularly by  the  administration  of  drugs. 

What  is  the  reaction  of  the  urine "? 

It  is  acid,  owing  to  the  presence  of  acid  phosphate  of  soda. 
After  standing  for  a  while  the  acidity  is  increased,  due  to  fer- 
mentation of  the  mucus  and  other  similar  products,  and,  at  the 
same  time,  with  this  increase  in  acidity,  urates  and  free  uric  acid 
are  deposited. 

Under  what  circumstances  outside  the  body  does  the 
reaction  become  alkaline  ? 
After  it  has  become  acid  it  changes  to  an  alkaline  reaction,  owing 
to  the  presence  of  ammonium  carbonate  derived  from  alterations 
of  the  urea.  At  the  same  time,  a  strong  ammoniacal  odor  ifl 
noticeable,  and  fetor,  with  deposits  of  triple  phosphates  and  alkaline 
urates,  appears. 

Does  the  reaction  of  the  urine  vary  in  different  animals  ? 
In  most  herbivora  it  is  alkaline  and  turbid,  but  this  difference 
depends  not  upon  a  different  mode  of  secretion,  but  upon    the 
variety  of  diet. 

Into   what  three  forms   is   the  urine  passed  at  different 
times  divided  ? 
Urina  potus,  urina  cibi,  and  urina  sanguinis. 


92         ESSENTIALS    OP    HUMAN    PHYSIOLOGY. 

What  is  the  difference  between  each  one  of  these  ? 

Urina  potus  is  secreted  immediately  after  drinking,  urina  cibi 
after  a  solid  meal,  and  urina  sanguinis  is  that  which  is  secreted 
early  in  the  morning  when  neither  food  nor  drink  has  been 
ingested. 

What  is  the  chief  solid  of  the  urine  ? 

Urea  is  the  chief  solid  constituent,  and  it  is  the  most  important 
ingredient  since  it  is  the  substance  by  which  the  nitrogen  of  de- 
composed tissue  is  given  off. 

What  is  the  result  when  this  urea  is  not  freely  eliminated 
from  the  body? 

It  produces  the  condition  known  as  uraemia,  in  which  the  patient 
has  convulsions  and  low  muttering  delirium  ending  in  death. 

Does  urea  exist  in  a  state  of  solution,  or  in  a  solid  form 
in  the  urine  ? 
In  a  state  of  solution. 

What  is  its  appearance  in  the  solid  state? 
It  forms  delicate,  silvery  acicular  crystals. 

What  is   the   quantity  of   urea   excreted   in  twenty-four 
hours  ? 
About  five  hundred  grains. 

Is  the  quantity  of  urea  per  day  influenced  by  diet  ? 

Yes.  Nitrogenous  or  animal  foods  increase  the  urea,  while  a 
purely  vegetable  diet  decreases  it. 

Is  there  any  difference  in  the  amount  secreted  by  males 
and  females  ? 

Males  secrete  more  than  females,  while  middle-aged  persons 
secrete  more  of  it  than  the  very  young  or  old.  Remember, 
however,  that  children  secrete  more  in  proportion  to  their  weight 
than  do  grown  persons. 

What  is  the  origin  of  urea  ? 

It  is  derived  from  two  sources :  first,  portions  of  unassimilated 
elements  of  nitrogenous  food  ;  second,  from  the  breaking  down  of 
tissue,  or  tissue  waste. 


THE    URINE.  93 

Does  urea  exist,  to  a  certain  extent,  preformed  in  the  blood, 
or  do  the  kidneys  manufacture  it  from  the  blood  ? 
Some  of  it  certainly  exists  ready  formed,  the  kidneys  merely 
extracting  it. 

What  is  uric  acid? 

An  acid  which  appears,  as  a  general  rule,  in  small  quantities  in 
the  urine  of  the  human  being,  and  which  is  entirely  absent  in  the 
cat  tribe.  The  quantity  of  it  varies  greatly  in  different  animals. 
In  birds  and  serpents  its  amount  greatly  exceeds  that  of  the  urea. 

In  what  way  is  the  quantity  of  uric  acid  increased? 

By  nitrogenous  food,  but  decreased  by  vegetable  food.  In  gout 
it  is  deposited  around  the  joints  as  the  urate  of  soda. 

From  what  does  uric  acid  arise  ? 

From  the  destruction  of  albuminous  matters.  The  relation 
between  urea  and  uric  acid  is  not  well  understood. 

What  is  hippuric  acid  ? 

It  is  found  in  man  and  is  allied  to  benzoic  acid.  Benzoic  acid 
is  eliminated  as  hippuric  acid. 

What  are  extractives  of  the  urine  ? 

They  consist  of  kreatin  and  kreatinin,  two  crystallizable  sub- 
stances derived  from  muscle  metamorphosis. 

What  are  the  saline  matters  of  the  urine  ? 

H2S04  in  the  urine  forms  a  compound  chiefly  or  entirely  with 
soda  or  potash,  thereby  forming  salts.  The  phosphoric  acid  also 
combines  and  forms  salts. 

The  breaking  down  of  what  tissues  increases  the  amount  of 
phosphates  in  the  urine  ? 
The  nervous  tissues. 

How  are  the  chlorides  formed? 

The  chlorine  combines  with  ammonia  and  potash  to  form  chlo- 
rides. 


94         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

Do  gases  exist  in  large  quantities  in  normal  mine? 

No;  in  very  small  quantities.  They  are  chiefly  COa  and 
nitrogen. 

"What  pathological  conditions  of  the  urine  occur  ? 

Albuminuria  is  a  condition  in  which  a  certain  amount  of  albu- 
men is  allowed  to  escape  from  the  system  by  the  kidneys.  At  one 
time  the  presence  of  albumen  in  the  urine  was  considered  to  be 
pathognomonic  of  Bright's  disease,  but  it  has  been  proved  that  it 
may  exist  physiologically  for  a  short  time  after  the  ingestion  of 
large  quantities  of  albumen.  Hematuria  is  a  condition  in  which 
there  is  blood  in  the  urine,  the  blood  coming  from  the  kidney  or 
any  portion  of  the  urinary  apparatus. 

What  is  hemoglobinuria  ? 

A  condition  in  which  free  haemoglobin  occurs  in  the  urine. 
Remember,  that  haemoglobinuria  is  not  hsematuria. 

What  is  choluria? 

The  presence  of  bile  in  the  urine.  It  occurs  in  certain  condi- 
tions in  which  the  circulation  of  the  portal  vein  is  disordered,  or 
after  the  ingestion  of  certain  poisons,  as,  for  example,  phosphorus. 

What  is  glycosuria  ? 

Glycosuria  is  the  presence  of  sugar  in  the  urine.  It  is  termed 
diabetes  mellitus. 

What  is  the  cause  of  diabetes  mellitus? 

It  is  either  produced  by  a  lesion  occurring  in  the  diabetic  centre 
in  the  floor  of  the  fourth  ventricle,  or  is  due  to  disorder  of  the 
circulation  of  the  liver  whereby  the  sugars  ingested  and  manufac- 
tured in  this  organ  are  improperly  distributed. 

What  is  chyluria  ? 

It  is  a  condition  in  which  the  chyle  from  the  digestive  tract  is 
passed  out  in  the  urine. 

What  is  diabetes  insipidus  ? 

A  condition  in  which  a  very  large  quantity  of  liquid,  of  a  low 
specific  gravity  and  containing  no  sugar,  is  passed. 


THE    SKIN.  % 


THE    SKIN. 

What  are  the  chief  functions  of  the  skin? 

It  acts  as  an  external  integument  for  the  protection  of  the 
deeper  tissues,  as  a  sensitive  organ  in  the  exercise  of  touch,  as  an 
important  excretory  and  absorbing  organ,  and  plays  a  highly 
important  part  in  the  regulation  of  the  bodily  temperature. 

Of  what  does  the  skin  consist? 

The  skin  consists  of  a  layer  of  vascular  tissue  named  the  corium, 
derma,  or  cutis  vera,  covered  by  a  layer  known  as  the  cuticle  or 
epidermis.  Underneath  and  within  the  corium  are  embedded 
several  organs  with  special  functions,  as  follows:  the  sudoriferous 
glands,  the  sebaceous  glands,  and  the  hair  follicles,  while  on  its 
surface  are  sensitive  papillae. 

Are  the  appendages  of  the  skin,  known  as  the  hair  and 
nails,  formed  frcm  the  corium  or  the  epidermis? 
They  are  modifications  of  the  epidermis. 

What  layer  of  the  epidermis  contains  the  pigment  in  colored 
races  ? 
The  layer  known  as  the  rete  mucosum. 

From  what  portion  of  the  skin  does  the  papillae  arise? 
They  are  conical  elevations  of  the  corium  or  true  skin. 

What  is  the  function  of  the  papillae  ? 

Nearly  every  one  of  them  contains  a  nerve  ending,  thereby 
increasing  the  peripheral  sensibility.  (For  the  corpuscles  of  touch, 
etc.,  see  the  Special  Senses,  "Touch.") 

What  is  the  function  of  the  cuticle  ? 

It  protects  the  papillse  from  injury  and  forms  a  check  on  undue 
evaporation  from  the  skin.  The  manner  in  which  it  protects 
sensibility  is  made  evident  when  we  remember  the  tenderness  of 
those  areas,  where,  by  constant  rubbing,  the  epidermis  is  rubbed  off. 


96         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  is  the  function  of  the  sudoriferous  glands  ? 

They  pour  out  the  sweat  on  the  surface  of  the  body  through 
ducts  which  at  first  are  spiral  but  which,  as  they  approach  the 
surface,  become  straight. 

Are  the  sudoriferous  glands  the  glands  which  secrete  the 
familiar  odors  in  the  axilla  and  elsewhere  ? 

No ;  the  glands  which  are  odoriferous  are  like  them  save  that 
they  are  larger  and  have  very  short,  straight  ducts. 

What  is  the  difference  between  sweat  and  perspiration? 

Sweat  is  applied  to  the  liquid  which  is  secreted  so  fast  that  it 
collects  in  drops;  perspiration,  to  the  moisture  which  is  continu- 
ously and  unconsciously  given  off  by  the  skin. 

What  is  the  function  of  sweat  and  perspiration  ? 

They  aid  in  the  dissipation  of  heat  by  their  evaporation  and 
thereby  reduce  the  bodily  temperature. 

How  much  watery  vapor  is  excreted  by  the  skin  in  twenty- 
four  hours? 

From  one  and  one-half  to  two  pints. 

How  much  C02  is  lost  in  this  manner  per  day  ? 

An  amount  which  is  almost  y^  to  ^j  of  the  amount  exhaled  by 
the  lungs,  and  which  differs  enormously  according  to  the  condi- 
tions surrounding  the  individual,  and  exercise,  food,  and  drink. 

What  other  impurities  are  given  off  by  the  skin   other 
than  C02  ? 

Urea  and  inorganic  salts. 

Is  the  excretory  function  of  the  skin  important  ? 

Exceedingly  so,  if  interfered  with  it  may  produce  death  by 
throwing  too  great  a  strain  on  the  kidneys,  for  remember  that  the 
skin  is  a  supplementary  organ  to  the  kidneys. 

In  what  ways  may  the  flow  of  perspiration  be  increased 
other  than  by  exercise  or  exposure  to  heat  ? 
If  a  localized  vaso-motor  palsy  occurs  sweating  sometimes  takes 


THE    SKIN.  97 

place ;  section  of  the  cervical  sympathetic  produces  copious  sweat- 
ing of  that  side  of  the  head. 

What  are  the  objects  of  the  sebaceous  glands  ? 

They  secrete  a  lubricating  fluid  or  oily  matter  which  keeps  the 
skin  soft  and  pliable. 

What  is  the  vernix  caseosa? 

That  sebaceous  matter  which  covers  the  skin  during  intra-uterine 
life. 

What  is  the  function  of  hair? 

It  acts  as  a  protection  from  cold,  as  when  on  the  head,  and  pro- 
tects the  skin  from  friction  in  the  axilla  or  on  the  pubis.  Besides 
protecting  the  head  from  changes  in  temperature,  it  wards  off 
blows  which  might  otherwise  be  serious  in  their  results  to  the 
more  vital  tissues. 

What  is  the  function  of  the  nails  ? 

To  protect  the  ends  of  the  fingers  from  injury  or  the  sensory 
papilla?  of  the  finger  tips  from  contact  with  harsh,  rough  objects, 
which,  if  it  occurred  constantly,  might  deprive  them  of  their  deli- 
cacy of  touch. 

Can  absorption  of  certain  substances  take  place   rapidly- 
through  the  skin? 
Very  rapidly.     A  familiar  example  of  this  is  the  ptyalism  pro- 
duced by  mercurial  inunctions. 

SECRETION. 

What  is  secretion  ? 

The  separation  from  the  blood  of  some  product,  directly  or  indi- 
rectly, by  the  vital  process  peculiar  to  a  gland  or  membrane.  This 
product  is  called  an  excretion  when  it  is  passed  out  of  the  body  as 
waste,  or  a  secretion  when  it  carries  out  some  function  in  the  animal 
economy. 

Give  a  good  example  of  an  excreting  gland? 
The  kidney. 


98         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

Give  an  example  of  a  secreting  gland. 

The  pancreas  or  mammary  gland? 

(For  the  manner  in  which  secretion  is  carried  on  in  each  gland, 
see  questions  on  each  subject.) 


THE    MAMMARY    GLANDS. 

What  changes  take  place  in  the  mammary  gland  during 
gestation  ? 
It  becomes  much  larger,  the  areola  around  the  nipple  increases 
in  width  and  deepens  in  color,  the  veins  become  more  prominent, 
while  the  lobules  can  be  plainly  felt. 

How  many  lobes  has  the  mammary  gland? 

From  fifteen  to  twenty,  each  one  of  which  is  divided  into  several 
lobules  made  up  of  acini. 

What  is  the  function  of  the  lactiferous  ducts  ? 

They  carry  the  secretion  to  the  nipple,  on  which  they  open  by  a 
number  of  orifices.  Just  before  they  enter  the  nipple  they  dilate, 
forming  little  sacs  which  collect  the  milk. 

In  what  way  are  the  fat  globules  of  milk  formed  ? 

They  are  supposed  to  be  the  results  of  a  physiological  fatty 
degeneration  of  the  cells  lining  the  acini  and  ducts. 
(For  Milk,  see  Articles  used  as  Foods.) 

THE    BODILY    METABOLISM. 

What  do  you  mean  by  the  term  Bodily  Metabolism? 

Those  phenomena  by  which  all  living  organisms  are  capable  of 
taking  substances  derived  from  their  food  into  their  tissues,  and 
making  them  an  integral  part  of  their  own  bodies  ;  further  than 
this,  metabolism  includes  the  breaking  down  of  these  tissues,  and 
the  removal  of  the  results  of  their  destruction;  the  first  half  of  the 
process  is  termed  assimilation,  the  second  half  excretion. 


MILK.  99 

Does  the  body  merely  assimilate  sufficient  food  to  replace 

exactly  those  particles  which  are  destroyed,  or  does 

it  do  more  than  this,  and  act  as  a  storehouse,  from 

which,  on  a  sudden  strain,  energy  may  be  derived? 

It  acts  as  a  storehouse  of  potential  energy,  which,  when  necessity 

arises,  it  may  transform  into  kinetic  energy. 

What  do  you  mean  by  potential  energy? 
That  energy  which  possesses  the  power  to  move,  but  is  quiescent. 

What  do  you  mean  by  the  term  kinetic  energy? 

Potential  energy,  when  exerting  its  influence,  either  by  pro- 
ducing motion  or  preventing  it,  is  called  kinetic  energy  ;  in  othei 
words,  potential  energy  is  latent,  kinetic  energy  is  active.  A 
coiled  watch-spring  held  firmly  represents  potential  energy,  but 
if  the  pressure  is  removed,  its  force  is  transformed  into  kinetic 
energy. 


GENERAL    VIEW    OF    THE    MOST 

IMPORTANT    SUBSTANCES 

USED    AS    FOOD. 

How  much  of  the  body  is  made  up  of  water  ? 

58.5  per  cent,  of  the  body  consists  of  water,  which  is  continually 
taken  in  and  given  off. 

What  is  the  purpose  of  water  in  the  organism  ? 

The  processes  of  digestion  and  absorption  require  the  presence 
of  water  for  the  solution  of  the  food,  and  it  is  also  used  to  carry  off 
the  effete  products.  So  much  water  exists  in  the  tissues  of  all 
animals  that  Hoppe-Seyler  has  put.it  that  all  organisms  live  in 
water. 

Milk. 

What  is  the  use  of  milk  and  its  preparations  ? 

Milk  forms  a  complete  typical  food,  in  which  are  all  the  con- 
stituents necessary  for  life  and  growth. 


100      ESSENTIALS    OF     HUMAN     PHYSIOLOGY. 

What  are  the  constituents  of  milk  ? 

In  every  ten  parts  of  proteids  we  have  ten  jjarts  of  fats  and 
twenty  parts  of  sugar. 

Describe  some  of  the  characters  of  milk. 

It  is  an  opaque,  bluish-white  liquid,  with  a  sweetish  taste  and  a 
characteristic  odor. 

What  is  this  odor  due  to  ? 

Probably  to  the  peculiar  volatile  aromatic  substances  derived 
from  the  cutaneous  secretion  of  the  glands. 

What  is  its  specific  gravity  ? 
1.026  to  1.035. 

What  is  the  reaction  of  human  milk  ? 

It  is  always  alkaline ;  cows'  milk  may  be  alkaline,  sometimes 
acid,  or  even  neutral.     The  milk  of  carnivora  is  always  acid. 

What  are  milk  globules  ? 

Small,  highly  refractive,  oil  globules  floating  in  a  clear  fluid,  the 
milk  plasma.     The  white  color  of  milk  is  due  to  their  presence. 

Of  what  do  the  globules  consist  ? 

Of  fat  or  butter,  surrounded  by  a  coating  of  casein. 

What  is  the  effect  of  churning  on  these  milk  globules? 

This  coating  of  casein  is  broken,  and  the  butter  globules  are 
allowed  to  run  together. 

What  does  the  milk  plasma  contain  aside  from  the  globules? 

It  contains  free  casein,  serum-albumin,  and,  to  a  less  extent,  a 
body  resembling  albumin,  the  lacto-protein  of  Millon  and  Lieber- 
mann. 

What  other  substances  have  we  in  milk  ? 

Galactin,  albuminose,  and  globulin ;  very  minute  traces  of  pep- 
tone are  also  present.  Milk  sugar,  a  carbohydrate  resembling 
dextrin,  and  urea  and  extractives  complete  the  list  of  its  con- 
stituents.   Remember,   that  the  casein  is  the  albuminous  portion 


MILK.  101 

of  milk  while  the  butter  globules  make  up    the  hydro-carbon 
portion. 

When  milk  is  boiled,  what  changes  take  place  in  it  ? 

The  serum-albumin  coagulates,  while  the  surface  also  becomes 
covered  with  a  layer  of  casein  which  has  become  insoluble. 

Is  raw  or  boiled  milk  most  digestible  ? 

The  raw  milk  ;  if  nature  had  intended  that  boiled  milk  should 
be  more  digestible  than  raw  milk,  raw  milk  would  have  been  formed 
with  the  same  conditions  present  that  exist  in  boiled  milk. 

Upon  what  does  the  coagulation  of  milk  depend  ? 
Upon  the  coagulation  of  its  casein. 

What  salt  in  milk  keeps  the  casein  in  solution  ? 

Calcium  phosphate;  which  is,  of  course,  destroyed  by  the  acid 
of  the  stomach.  Remember,  that  milk  coagulates  in  the  stomach, 
not  on  account  of  the  acid,  but  owing  to  the  presence  of  a  milk- 
curdling  ferment.     (See  page  63,  Digestion.) 

What  causes   the   spontaneous  coagulation  or  souring  of 
milk? 
It  is  produced  by  the  development  of  lactic  acid,  which  is  formed 
from  the  milk  sugar  by  the  action  of  the  bacterium  lacticum. 

What  is  the  difference  between  human  milk  and   cow's 
milk? 
It  contains  less  albumin,  and  the  albumin  it  does  contain  is 
more  soluble  than  that  in  cow's  milk.     It  also  contains  more  sugar 
and  fats  than  does  cow's  milk. 

What  is  colostrum  ? 

It  is  the  substance  which  is  secreted  at  the  beginning  of  lacta- 
tion, and  contains  much  serum-albumin,  and  very  litt'.e  casein, 
while  all  the  other  substances,  specially  the  fats,  occur  in  large 
amount. 

What  is  the  purpose  of  colostrum? 

Containing,  as  it  does,  a  large  amount  of  fat,  it  acts  as  a  purga- 
tive, and  sweeps  out  the  meconium  and  other  effete  products  from 
the  alimentary  canal  of  the  infant. 


102       ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

Are  gases  found  in  ordinary  milk? 
Only  in  minute  traces. 

What  salts  are  found  in  milk? 

The  potash  salts  are  much  more  plentiful  than  the  soda  salts ; 
there  is  also  a  large  amount  of  calcium  phosphate  present. 

What  is  the  purpose  of  the  calcium  phosphate  ? 

It  is  necessary  in  the  formation  of  the  bones  of  the  infant. 

What  difference  is  there  in  the  composition  of   milk  at 
various  times? 
That  drawn  last  is  always  richer  in  butter,  while  if  the  ducts 
are  emptied  frequently  the  butter  decreases  but  the  casein  increases. 

Are  egg-s  a  typically  complete  food  ? 

They  are  not  as  complete  a  food  as  is  milk,  but  are  the  most 
typical  food  next  to  milk. 

What  is  the  object  attained  by  cooking  flesh? 

It  breaks  up  to  a  certain  extent  the  elastic  coverings  of  the 
muscular  fibre,  softens  the  connective  tissues,  and  renders  it  more 
tender  and  easy  of  digestion. 

In  the  vegetable  foods,  what  are  the  chief  nitrogenous 
substances? 
Gluten  is  the  most  abundant  nitrogenous  substance  present,  and 
occurs  immediately  under  the  husk. 

How  many  groups  of  foods  are  necessary  for  the  main- 
tenance of  health  in  man? 
Five. 

What  substances  make  up  these  groups  ? 

First,  the  starches,  which  are  used  for  the  purpose  of  adding 
heat  to  the  body,  and  also  fat ;  second,  the  fats,  which  are  used 
for  the  purpose  of  maintaining  the  bodily  heat  and  retaining  it; 
third,  albuminous  foods,  whose  function  is  to  add  force  to  the 
system ;  fourth,  water,  which  is  necessary  for  the  carrying  out  of 
the  vital  processes ;  and  fifth,  salts,  which  are  also  absolutely 
needful  for  the  maintenance  of  health. 


MILE.  103 

What  is  the  absolute  amount  of  the  different  food-stuffs 
required  by  an  adult  in  twenty-four  hours? 
It  varies  enormously  according  to  the  surrounding  conditions, 
but,  as  a  general  rule,  it  sbould  contain  130  grammes  of  proteids, 
84  grammes  of  fats,  and  41)4  grammes  of  carbohydrate-.  Remember, 
that  the  carbohydrates  should  always  be  greatly  in  excess  of  the 
nitrogenous  principles. 

What  effect  has  the  withdrawal  of  all  forms  of  food-stuffs, 
with  the  exception  of  one  particular  class,  upon 
nutrition  ? 
The  animal  wastes,  and  finally  dies  with  very  much  the  same 

symptoms  as  would  follow  starvation. 

The  manner  in  which  effete  products  art'  taken  up  and  excreted 
has  already  been  considered  (see  Circulation,  Respiration,  and  the 
Kidney  and  Urine). 

What  process  goes  on  during  starvation? 

All  food  being  taken  away  from  the  body  the  organism  is  re- 
quired to  abstract  at  first  the  unimportant  tissues  in  order  to  keep 
up  its  vital  processes.  After  this  the  wasting  becomes  marked, 
and  the  bodily  weight  falls.  Weakness,  the  result  of  the  breaking 
down  of  vital  tissues,  comes  on,  and  finally  death,  after  all  sub- 
stances capable  of  supplying  force  in  the  body  have  been  used  up, 
save  those  actually  concerned  in  the  vital  processes. 

How  long  will  the  average  adult  survive  without  food? 

About  twenty-one  to  twenty-four  days,  although  cases  are  on 
record  of  survival  for  forty-one  days. 

How  much  bodily  weight  is  lost  before  death? 
Four-tenths  of  the  bodily  weight. 

Are  fats  ever  formed  from  proteids  ? 

Yes ;  as  an  example  of  this,  the  cdw  does  not  consume  as  much 
fat  in  a  day  as  she  gives  in  butter. 


104      ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 


THE    MUSCLES.1 

What  is  the  function  of  the  muscles? 

To  produce  movements,  which  vary  according  to  the  rapidity 
and  power  of  their  contraction. 

In  what  way  do  the  voluntary  muscles  act  upon  the  hones  ? 

As  levers.  They  are  often  attached  to  the  short  arm  of  the  lever, 
and  while  this  is  apparently  a  disadvantage,  since  under  these 
circumstances  greater  force  is  required  to  lift  a  given  weight,  it,  in 
reality,  is  of  the  greatest  service,  since  slight  contractions  of  muscles 
cause  very  extensive  and  rapid  movements  of  the  part. 

How  many  orders  of  levers  are  met  with  in  the  movements 
of  the  different  hones  of  the  skeleton  hy  the  muscles  ? 

All  three;  and  in  some  cases  all  three  occur  at  the  same  joint. 

Give  an  example  of  the  first  order  of  levers. 

When  the  triceps  is  the  power  which  draws  upon  the  olecranon, 
thus  moving  the  hand  and  forearm  around  the  trochlea,  which  acts 
as  the  fulcrum. 

Give  an  example  of  the  second  order. 

This  occurs  when  the  hand,  resting  on  a  point  of  support,  acts  as 
the  fulcrum,  and  the  triceps  pulling  on  the  olecranon  is  the  power 
which  raises  the  humerus,  upon  which  is  fixed  the  body  or  weight. 

Give  an  example  of  the  third  order. 

This  is  exemplified  by  the  action  of  the  biceps  in  ordinary  flexion 
of  the  elbow,  in  which  the  biceps  is  attached  to  the  upper  portion 
of  the  forearm. 

What  two  varieties  of  muscular  fibre  have  we  ? 

Two ;  striped,  or  striated  or  voluntary  ;  unstriped,  unstriated  or 
involuntary.  The  first  group  are  moved  entirely  by  the  will-power, 
or  by  centres  under  the  control  of  the  will-power.  The  second 
group,  solely  by  nervous  centres  over  which  the  will-power  has  no 
direct  influence. 

1  The  anatomy  of  muscles  is  to  be  found  in  anatomical  text-books. 


THE    MUSCLES.  105 

What  large  mass  of  striped  muscular  fibre  is  an  exception 
to  this  rule? 
The  heart,  which,  although  it  is  made  up  of  striped  muscle,  beats 
independently  of  the  will.  The  arrangement  of  the  heart  muscle, 
however,  is  somewhat  different  from  striped  muscular  fibres  else- 
where. 

What  is  the  difference  in  the  contraction  of  striped  and 
unstriped  muscular  fibre? 
The  striped  muscular  fibre  usually  contracts  more  rapidly. 

What  is  the  consistency  of  muscle  ? 

The  contractile  substance  of  muscle  is  so  soft  as  to  be  almost 
fluid,  being  of  the  consistency  of  jelly. 

What  is  the  chemical  composition  of  muscle  ? 

As  already  pointed  out  elsewhere,  it  is  impossible  to  determine 
this  during  life,  since  the  analysis  produces  death.  Muscle,  how- 
ever, contains  the  substances  known  as  muscle-serum  and  muscle-clot 
or  myosin,  which  are  the  result  of  certain  chemical  changes  occur- 
ring after  death. 

What  effect  has  coagulation  of  the  myosin  in  muscle  ? 

Its  formation  is  followed  by  "rigor  mortis,"  or  post-mortem 
rigidity. 

In  what  way  can  this  coagulation  be  postponed? 

By  keeping  the  muscle  at  a  temperature  but  a  few  degrees  above 
freezing  point.  If  a  muscle  be  kept  in  this  manner,  pressure  will 
cause  the  exudation  from  it  of  a  yellow,  opalescent,  alkaline  juice, 
which  on  still  further  cooling  changes  into  a  jelly. 

What  effect  has  warming  of  this  jelly  ? 

It  passes  through  the  stages  of  coagulation  seen  in  ordinary 
muscle  after  death,  producing  the  same  fluid  serum  and  muscle-clot 
or  myosin. 

What  is  this  muscle  juice  sometimes  called  ? 

Muscle  pins) na,  which  is  supposed  to  be  the  contractile  matter  in 
living  muscle. 


106      ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  does  the  coagulation  of  muscle  plasma  very  closely 
resemble  ? 

The  coagulation  of  blood  plasma,  with  the  difference  that  the 
muscle  clot  is  gelatinous  and  not  in  threads,  as  is  fibrin.  It  is  a 
globulin,  and  is  soluble  in  a  two  per  cent,  solution  of  common  salt. 
Remember,  that  this  globulin  forms  the  greater  portion  of  albu- 
minous matter  in  muscle. 

What  is  the  difference  between  the  reaction  of  muscles 
before  and  after  death  ? 
Before  death  they  are  alkaline ;  after  death,  acid. 

Of  what  does  the  serum  of  the  muscle  consist  beside  the 
albuminous  principles  ? 

1st,  kreatin,  kreatinin,  and  xanthin  ;  2d,  haemoglobin ;  3d,  grape 
sugar,  muscle  sugar  or  inosit,  and  glycogen  ;  4th,  sarcolactic  acid, 
made  from  the  inosit  by  fermentation ;  5th,  carbonic  acid ;  6th, 
potassium  salts ;  and,  7th,  75  per  cent,  of  water. 

What  do  you  mean  by  the  elasticity  of  muscle  ? 

The  degree  to  which  the  muscle  can  be  stretched  and  still  return 
to  its  normal  length.  If  a  given  weight  be  applied  to  the  end  of 
a  muscle,  it  is  stretched  a  certain  distance;  but  an  additional 
weight  or  weights  do  not  produce  by  any  means  an  elongation 
equal  to  the  first.  The  elongation,  on  additional  strain,  is  con- 
stantly decreased  in  extent. 

Is  there  any  variation  in  the  elasticity  of  muscles? 

At  first  a  strain  on  a  muscle  produces  very  rapid  extension ;  but 
this  is  constantly  decreased  as  time  goes  on,  finally  ceasing. 
Muscles  which  are  fatigued  are  more  readily  stretched  than  fresh 
ones. 

What  difference  is  there  between  the  elasticity  of  dead 
and  living  muscle  ? 
Dead  muscle  possesses  less  elasticity  and  requires  a  greater 
weight  to  stretch  it.  It  can  be  stretched  further  than  living 
muscle,  but  does  not  return  to  its  former  length  as  completely  as 
the  normal  muscle. 


THE    MUSCLES.  107 

Are  the  muscles  of  the  body  always  on  the  stretch,  and  if 
so,  what  is  the  object  reached  by  this  condition? 
They  are  always  on  the  stretch,  even  when  passive,  and  act  as 
ligaments  which  hind  together,  in  a  compact  mass,  the  entire  body. 
Muscles  nearly  always  have  opposing  muscles  whose  function  it  is 
when  exercised,  to  produce  opposite  movements.  The  elasticity 
of  these  muscles,  in  a  passive  state,  also  opposes  active  contraction 
in  the  opposite  muscle,  which  is,  however,  easily  overcome.  After 
the  active  contraction  has  taken  place,  the  elasticity  of  the  passive 
muscle  acts  as  a  weak  spring,  therehy  keeping  up  the  tonicity  of 
the  limb  and  preventing  sudden  jerkings  of  the  body,  as  would 
occur  if  a  muscle  should  contract  suddenly  and  "  take  up  the 
slack"  in  the  opposite  muscle. 

What  electrical  phenomena  have  we  in  muscle  ? 

In  the  normal  living  muscle  we  have  invariably  present  an 
electric  current  known  as  the  natural  muscle  current. 

What  circumstances  influence  this  current  ? 

It  is  greatly  reduced  by  fatigue  and  loss  of  vital  power,  and  is 
generally  supposed  to  be  absent  in  perfectly  normal  passive  muscle 
lying  in  situ.  As  soon  as  the  muscle  is  moved  or  disturbed  by 
partial  removal  from  the  body  the  current  develops. 

What  do  you  mean  by  "negative  variation"  in  muscle? 

If  a  muscle  be  connected  with  a  galvanometer  so  as  to  measure 
its  natural  current  and  then  be  stimulated  to  a  contraction  by 
means  of  the  nerve  trunks,  a  marked  decrease  occurs  in  the 
current.  The  galvanometric  needle  swings  toward  the  zero  point, 
showing  that  the  current  is  weakened  and  destroyed.  This  is 
called  the  negative  variation,  and  precedes  the  change  to  an  active 
condition  of  the  muscle. 

What  do  you  mean  by  the  irritability  of  the  muscle  ? 
The  capability  with  which  a  muscle  passes  into  contraction. 

What  are  the  usual  causes  of  contraction  of  the  voluntary 
muscles  ? 
They  contract  ordinarily  in  response  to  impulses  communicated 


108      ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

to  them  by  nerves,  the  impulse  originating  in  the  brain  or  spinal 
cord.  The  will  power  is  the  most  common  cause  of  contraction 
of  the  skeletal  muscles. 

What  other  conditions  may  produce  contractions  of  the 
muscles  ? 
Contraction  of  the  muscles  may  be  produced  either  by  the  appli- 
cation to  them  directly  of  some  irritating  or  stimulating  substance, 
or  by  the  application  of  stimulation  to  their  supplying  nerves. 

Is  it  possible  to  cause  contraction  in  muscular  fibre  which 
is  devoid  of  terminal  nerve  filaments,  or,  in  other 
words,  does  the  contraction  of  a  muscle  necessarily 
depend   upon  the    presence   of    peripheral   motor 
nerves  ? 
That  muscles  may  be  stimulated  to  contraction  without  the  in- 
tervention of  nerve  fibres,  is  proved  by  the  fact  that  some  parts 
of  muscles,  as  the  lower  end  of  the  sartorius,  respond  energetically 
to  all    forms  of   muscle  stimuli,  though  they  possess  no   nerve 
endings ;  there  are  some  substances,  too,  which  produce  contrac- 
tion of  muscles  on  direct  application,  which  will  not  produce  that 
contraction  when  applied  to  the  nerve  trunk,  as,  for  example, 
ammonia.     Again,  the  muscles  will  generally  respond  to  various 
stimuli  long  after  the  nerve  supplying  them  has  been  killed  by 
exposure,  and  curare,  which  paralyzes  the  peripheral  ends  of  the 
motor  nerves  in  the  muscles,  in  no  way  prevents  the  contraction 
of  the  muscle  itself  when  it  is  directly  stimulated. 

What  forms  of  muscle  stimuli  have  we  ? 

First,  mechanical  stimulation,  as  by  a  sudden  blow  or  pinch, 
resulting  in  momentary  transient  contraction.  Second,  thermic 
stimulation.  Contraction  of  the  muscle  takes  place  if  the  tem- 
perature be  raised  or  lowered.  This  contraction,  however,  is 
scarcely  identical  with  ordinary  muscular  contractions,  since  it  is 
a  prolonged  spastic  contraction  of  an  abnormal  type.  Third, 
chemical  stimulation,  which  may  produce  contractions  by  irri- 
tating mineral  and  organic  acids,  various  metallic  and  neutral 
salts.  Fourth,  electrical  stimulation,  which  is  the  most  common 
form  employed,  and  gives  the  most  satisfactory  results. 


THE    MUSCLES. 


109 


At  what  time  during  the  application  of  an  electrical  current 
to  a  muscle  does  the  contraction  take  place  ? 
Remember  that  it  takes  place  not  while  the  current  is  passing 
through  the  muscle,  but  at  the  moment  the  current  is  turned  on 
or  turned  off,  or  is  suddenly  increased  or  decreased  in  strength. 
A  constant  current  of  exactly  even  intensity  may  be  made  to  pass 
through  a  muscle  without  exciting  contraction. 

Is  the  stimulus  necessary  to  produce  contraction  in  a  muscle 
when  applied  to  its  nerve  trunk,  sufficient  to  pro- 
duce the  same  degree  of  contraction  in  the  muscle 
when  applied  to  the  muscle  itself? 
No,  it  is  not. 

What  are  the  chemical  changes  resulting  in  a  muscle 
during  its  contraction? 
Its  neutral  or  faintly  alkaline  reaction  becomes  for  the  moment 
acid,  owing  to  the  formation  of  sarco-lactic  acid.  More  oxygen 
is  taken  up  from  the  blood  than  when  the  muscle  is  at  rest.  A 
greater  amount  of  carbon  dioxide  is  given  off,  but  the  change  in 
the  quantity  of  C02  has  no  exact  relation  to  the  quantity  of  oxygen 
used.  A  diminution  is  said  to  occur  in  the  glycogen  of  muscle, 
and  a  peculiar  muscle  sugar  makes  its  appearance. 

What  changes  occur  in  the  elasticity  of  the  muscle  during 
contraction? 
The  elasticity  is  less  than  when  it  is  in  a  passive  state — that  is, 
a  given  weight  will  stretch  a  contracted  muscle  more  than  a  passive 
muscle,  but  the  return  to  the  normal  length  of  the  muscle  is  not 
so  complete,  or,  in  other  words,  extensibility  is  increased,  elasticity 
is  decreased. 

What  effect,  therefore,  has  stimulation  of  a  muscle  which 

is  overloaded  by  a  weight  greater  than  it  can  lift  ? 

When  stimulation  is  applied  to  such  a  muscle  we  get  elongation 

instead  of  contraction,  because  of  the  rule  just  now  given,  namely, 

that  the  active  state  lessens  the  elastic  power  of  the  muscle. 


110      ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  effect  has  stimulation  of  one  part  of  a  muscle  upon 
the  rest  of  the  muscle  ? 
A  contraction  wave  passes  from  the  part  stimulated  over  the 
whole  mass. 

What  effect  has  the  activity  of  muscle  fibre  upon  its 
temperature  ? 
It  raises  it  very  markedly,  the  production  of  heat  being  in 
direct  proportion  to  the  tension  of  the  muscle.  If  the  muscle  be 
kept  in  a  state  of  constant  activity,  so  that  fatigue  is  produced,  the 
temperature  falls. 

What    change    in    shape    takes    place    in   the    muscle  on 
contraction? 
It  shortens,  and  in  direct  ratio  with  its  shortening  its  thickness 
increases.     There  is,  therefore,  but  little  change  in  bulk,  but  con- 
siderable change  in  shape. 

What  do  you  mean  by  the  "latent  period"  ? 

The  short  space  of  time  which  elapses  between  the  moment  of 
stimulation  of  a  muscle  and  the  beginning  of  its  contraction.  In 
the  voluntary  muscle  of  the  frog  this  lasts  only  about  one-tenth  of 
a  second. 

What  do  you  mean  by  the  period  of  "rising  energy"? 

The  space  of  time  during  which  contraction  occurs  first  slowly, 
then  more  quickly,  then  more  slowly. 

What  do  you  mean  by  the  term  "falling  energy"? 

The  period  at  which  relaxation  of  the  muscle  takes  place.  At 
first  slowly,  then  more  quickly,  finally,  more  slowly. 

Is  there  any  pause  at  the  height  of  contraction  before 
relaxation  begins  ? 
No,  none  at  all. 

Is  there  any  variation  in  the  rapidity  of  contraction  of 
different  muscles  ? 
Yes,  an  enormous  difference  exists  not  only  in  various  animals, 
but  in  the  same  muscles  of  a  single  individual.     As  an  example 


THE    MUSCLES.  Ill 

of  the  difference  in  rapidity  of  contraction  in  the  muscles  of  dif- 
ferent animals,  may  be  mentioned  the  fact  that  while  the  unstriped 
muscular  tissue  of  a  mollusc  occupies  several  minutes  for  its  con- 
traction, the  muscle  of  the  wing  of  a  horse-fly  contracts  330  times 
a  second.  The  variation  and  rapidity  of  contraction  differ  very 
largely  with  the  needs  and  habits  of  the  animal. 

What  do  you  mean  by  the  "  maximum  contraction  "  of  a 
muscle  ? 
The  greatest  shortening  which  can  be  produced  by  a  single  in- 
stantaneous impulse  or  stimulus. 

What  do  you  mean  by  the  term  "  over-maximal  contrac- 
tion "  ? 
If  the  current  be  increased  after  the  maximum  contraction  is 
reached,  a  second  and  still  further  contraction  occurs.     This  is 
called  the  over-maximal  contraction. 

What  do  you  mean  by  the  term  "  summation  "  ? 

If  a  muscle  be  caused  to  contract  by  a  shock  of  medium  strength, 
it  contracts  to  its  maximum;  but  if  a  second  shock  be  given  while 
the  muscle  is  contracting  from  the  first  shock,  a  new  maximum 
contraction  is  added  to  that  already  under  wray.  This  is  called 
the  summation  of  effect. 

What  do  you  mean  by  the  "  tetanus  "  ? 

A  condition  of  a  muscle  in  which  it  apparently  remains  in  a 
constant  state  of  contraction — or,  in  other  words,  a  summation  of 
contractions  exists.  To  produce  artificial  tetanus,  impulse  after 
impulse  must  be  transmitted  to  the  muscle  with  great  rapidity, 
otherwise  between  each  stimulus  the  muscle  will  partially  relax 
or  attempt  to  pass  into  the  condition  known  as  falling  energy. 

Upon  what  does  the  irritability  and  fatigue  of  a  muscle 
depend  ? 
Upon  the  amount  of  labor  required  and  the  nourishment  supplied 
by  the  blood.     Fatigue  means  lessened  irritability. 


112         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

THE  NERVOUS  SYSTEM. 

What  is  the  nerve  trunk  made  up  of  ? 

First,  the  primitive  fibril,  which  is  the  simplest  form  of  nerve 
filament,  and  is  visible  only  with  a  very  high  power  of  the  micro- 
scope. 

Is   the   primitive   fibril   the    same    thing    as    the    axis 
cylinder  ? 

No;  the  axis  cylinder  is  made  up  of  bundles  of  the  primitive 
fibrils  held  together  by  a  slightly  granular  element. 

Give  a  description  of  a  complete  nerve. 

It  is  made  up  of:  1st.  The  primitive  fibril.  2d.  The  naked 
axial  cylinder.  3d.  The  clothed  axis  cylinder,  covered  by  the 
white  substance  of  Schwann,  or  the  medullary  sheath,  or  the 
myelin.  4th.  The  clothed  axis  cylinder  covered  by  the  sheath  of 
Schwann,  or  the  neurilemma.  5th.  The  clothed  axis  cylinder  with 
both  these  coverings,  or  the  complete  nerve. 

What  is  the  difference  between  the  fibres  of  the  cerebro- 
spinal system  and  those  of  the  sympathetic  system  ? 
Those  of  the  first  are  formed  as  the  nerves  of  the  5th  group  just 
given,  while  the  sympathetic  are  made  up  of  axis  cylinders  covered 
by  the  sheath  of  Schwann,  or  neurilemma,  as  in  the  4th  group. 

What  is  the  function  of  Ranvier's  nodes  ? 

They  are  supposed  to  permit  the  diffusion  of  plasma  from  outside 
into  the  axis  cylinder,  and  thereby  to  aid  the  nutrition  of  the  nerve. 

What  are  the  nervi-nervorum  ? 

They  are  small  nerves  which  accompany  the  nerve  sheaths, 
thereby  endowing  them  with  sensibility. 

Give  some  facts  in  regard  to  the  chemistry  of  the  nervous 
substance. 
Albumin  occurs  chiefly  in  the  axis  cylinder  and  in  the  sub- 
stance of  the  ganglionic  cells.  Potash,  albumin,  and  a  globulin-like 
substance  are  also  present.  Another  substance  of  the  same  char- 
acter is  nuclein,  which  occurs  especially  in  the  gray  matter,  and 
neuro-keratin,  a  body  resembling  keratin  and  which  contains 
much  sulphur.  The  connective  tissue  of  nerves  yields  gelatin, 
but  the  sheath  of  Schwann  only  yields  elastin.  In  addition  to 
these  we  have  cerebrin,  lecithin,  and  protagon. 


THE    NERVOUS    SYSTEM.  113 

What  is  the  chemical  reaction  of  nervous  matter  ? 

When  passive  it  is  neutral  or  feebly  alkaline;  while  active  and 
after  death  it  is  acid. 

What  difference  is  there  between  the  reaction  of  the  ner- 
vous matter  in  general  and  the   reaction  of   the 
brain  ? 
The  gray  matter  of  the  brain  is  supposed  to  be  always  acid, 

while  the  other  is  not. 

Have  nerves  great  or  slight  tensile  strength  ? 

They  possess  great  strength,  for  it  is  a  well-known  fact  that  in 
cases  where  by  accident  the  arm  is  torn  off,  the  nerve  is  the  only 
part  not  ruptured.  Tillaux  has  found  that  the  sciatic  nerve  will 
hold  a  strain  of  as  much  as  120  pounds. 

What  is  the  function  of  the  nervous  system  ? 

It  is  the  apparatus  by  which  distant  parts  of  the  body  are  kept 
in  constant  relationship  with  one  another  so  that  a  change  of 
condition  in  any  one  spot  is  communicated  to,  and  may  set  up 
corresponding  changes  in,  remote  parts. 

What  two  divisions  have  we  of  nerve  fibres  ? 

The  afferent  or  centripetal,  and  the  efferent  or  centrifugal ;  most 
nerves  contain  both  sets  of  fibres. 

Do  nerve  fibres  possess  the   power  of  generating  force  in 
themselves  ? 
They  do  not.     Neither  are  they  capable  of  originating  impulses. 
They  are  functionally  inactive  until  they  receive  impulses  from 
higher  nerve  centres. 

What  is  the  distinction  between  the  white  and  the  gray 
nerves  ? 
The  white  nerves  contain  the  white  substance  of  Schwann,  the 
gray  nerves  do  not. 

Which  of  these  two  varieties  is  the  most  common  ? 

The  white  by  far,  since  the  gray  are  contained  chiefly  in  the 
sympathetic  system  and  parts  of  the  organs  of  special  sense. 

8 


114        ESSENTIALS     OF     HUMAN     PHYSIOLOGY. 

What  is  the  function  of  an  afferent  or  centripetal  nerve  ? 

To  carry  impulses  from  the  periphery  to  the  centre  which  may 
receive  them. 

What  is  the  function  of  an  efferent  or  centrifugal  nerve  ? 

To  carry  impulses  from  the  centre  to  the  periphery,  which 
impulses  may  arise  of  themselves  in  the  central  nervous  system  or 
be  excited  reflexly  through  a  sensory  nerve. 

Are  impulses  travelling  along  one  nerve  trunk  ever  trans- 
ferred to  another  nerve  trunk  running  near  by  ? 
No,  never,  under  any  circumstances,  if  both  nerves  are  intact. 

How  many  divisions  have  we  of  efferent  nerves  ? 

First,  motor,  or  nerves  going  to  muscles  causing  them  to  contract; 
second,  secretory,  which  call  forth  the  activity  of  glands ;  third, 
inhibitory,  which  check  or  prevent  some  activity  ;  fourth,  vaso- 
motor nerves,  which  regulate  the  contraction  of  the  muscular  coat 
of  the  bloodvessels,  and  trophic,  thermic,  and  electric  nerves,  all 
of  which  are  doubtfully  in  existence,  save  the  electric,  which  occur 
in  animals  capable  of  emitting  electrical  discharges. 

What  do  you  mean  by  inter-central  nerves  ? 

Inter-central  nerves  are  those  which  act  as  bonds  of  union 
between  the  cells  of  nerve  centres. 

What  is  the  velocity  of  nerve  force  ? 

It  is  about  at  the  rate  of  thirty  metres  per  second,  or  the  speed 
of  a  fast  express  train,  so  that  impulses  can  only  travel  from  one 
portion  of  a  man's  body  to  another  at  about  the  same  rate  as  an 
express,  or  about  twice  as  fast  as  the  fastest  horse  can  gallop. 

What  do  you  mean  by  "  negative  variation  "  ? 

The  natural  current  of  a  nerve,  like  that  of  a  muscle,  undergoes 
a  diminution  at  the  moment  the  nerve  is  stimulated  ;  this  is  termed 
the  negative  variation.  The  negative  variation  travels  along  the 
nerve  at  just  the  same  velocity  as  the  impulse  does  from  the  point 
of  stimulation  ;  as  a  consequence  of  this  the  negative  variation  and 
nerve  impulse  are  believed  to  be  identical. 


THE    NERVOUS    SYSTEM.  115 

What  do  you  mean  by  electrotonus  ? 

Electrotonu.s  may  be  defined  as  the  electrical  condition  of  a 
nerve,  which  undergoes  constant  variation  according  to  the  circum- 
stances affecting  it.  This  will  be  more  clear  after  the  question  on 
anelectrotonus  and  katelectrotonus  has  been  read. 

What  do  you  mean  by  the  terms  anelectrotonus  and 
katelectrotonus  ? 
Anelectrotonus  is  the  term  applied  to  the  condition  of  the  nerve 
near  the  anode,  or  positive  pole,  during  the  passage  of  a  constant 
electrical  current,  the  irritability  of  the  nerve  being  decreased  in 
this  region.  Katelectrotonus  is  applied  to  the  part  of  the  nerve  near 
the  cathode,  or  negative  pole,  the  irritability  being  here  increased. 

What  do  you  mean  by  the  irritability  of  nerves  ? 

The  condition  which  permits  of  the  transmission  of  impulses 
*rom  more  or  less  powerful  stimuli. 

What  conditions  are  necessary  for  this  irritability  ? 

A  perfect  supply  of  blood,  to  bring  nourishment  and  carry  away 
effete  matters,  an  uninjured  connection  with  the  nerve  centres, 
and  a  normal  temperature. 

What  is  the  result  if  the  blood  supply  of  a  nerve  is  cut  off? 
The  nerve  rapidly  loses  its  excitability,  and  finally  becomes 
paralyzed. 

Supposing  a  nerve   is  exhausted  by  fatigue    or   lack  of 
blood  supply,  how  does  recovery  occur  ? 
When  a  nerve  recovers  it  does  so  slowly,  then  more  rapidly,  and 
afterward  more  slowly. 

At  what  portion  of  the  nerve  trunk  would  you  apply  the 

stimulus  to  produce  the  greatest  contraction  in  the 

tributary  muscle,  or,  in  other  words,  at  what  point 

would  you  find  the  greatest  irritability  of  the  nerve? 

At  some  part  of  the  nerve  distant  from  the  muscle.     The  further 

from  the  muscle  the  more  powerful  is  the  contraction  produced. 

The  impulse  seems  to  gather  force  as  it  goes  along  the  nerve. 


116        ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What   do   you    mean   by  the    "indifferent    point"    of    a 
nerve  ? 

As  already  stated,  when  a  constant  current  is  applied  to  a  nerve 
its  irritability  is  greater  in  the  neighborhood  of  the  cathode,  but  is 
diminished  in  the  neighborhood  of  the  anode.  Near  the  middle 
of  the  nerve,  or  rather  a  point  about  half  way  between  each  pole, 
we  have  an  area  known  as  the  indifferent  point ,  since  at  this  portion 
the  increased  irritability  of  the  cathode  no  longer  exists,  nor  does 
the  diminished  irritability  of  the  anode  occur.  This  indifferent 
point  is  not  always  midway  betweeen  the  two  poles,  since  variations 
in  the  strength  of  the  current  influence  its  position. 


What  are  the  laws  of  contraction  1 

1.  In  all  muscles,  when  the  current  is  broken,  the  disappearance 
of  anelectrotonus  is  the  cause  of  the  stimulation.  2.  When  the 
current  is  made  it  is  the  appearance  of  katelectrotonus  which 
causes  the  stimulation.  3.  With  the  same  current  the  contraction 
produced  with  the  making  of  the  current  is  more  than  the  contraction 
which  occurs  on  the  breaking  of  the  current.  4.  Anelectrotonus 
causes  reduction  of  irritability  and  conductivity.  5.  Katelectrotonus 
causes  increase  of  irritability.  6.  With  ascending  currents,  the 
portion  of  the  nerve  next  to  the  muscle  is  in  a  state  of  reduced 
functional  activity  or  anelectrotonus.  7.  With  descending  cur- 
rents the  part  of  the  nerve  next  the  muscle  is  in  a  state  of  exalted 
activity — katelectrotonus.  8.  These  changes  are  much  weaker  with 
weak  currents  than  with  strong  ones. 


What  do   you    mean   by   the   term   nerve    corpuscles    or 
terminals  ? 

Those  small  nerve  bodies  or  corpuscles  in  which  nerve  fibres  end 
and  through  which  efferent  nerve  fibres  give  off  their  impulses 
and  afferent  nerve  fibres  receive  their  impulses.  Those  which  are 
attached  to  the  endings  of  sensory  or  afferent  nerves  of  the  skin 
are  known  as  tactile  corpuscles. 


PHYSIOLOGY    OF    THE    SPINAL    NERVES.       117 

PHYSIOLOGY    OF    THE    SPINAL 
NERVES. 

It  will  be  remembered  that  thirty-one  pairs  of  spinal  nerves 
leave  the  vertebral  canal  between  the  vertebrae,  in  contradistinc- 
tion to  the  cranial  nerves,  which  come  out  from  the  base  of  the 
skull,  and  that  each  pair  of  nerves  is  attached  to  the  spinal  cord 
by  two  roots,  known  as  the  anterior  and  posterior,  which  becoming 
united  pass  through  the  intervertebral  canal,  forming  one  trunk. 
Just  before  the  junction  of  the  two  roots  it  will  also  be  remembered 
that  the  posterior  root  is  enlarged  by  a  ganglionic  swelling.  The 
spinal  nerves  are,  therefore,  sometimes  called  mixed  nerves,  for  the 
reason  that  they  contain  both  efferent  and  afferent  fibres.  Those 
going  from  the  anterior  portion  of  the  spinal  cord  carry  the  motor 
or  efferent  impulses,  those  coming  to  the  posterior  part  of  the 
spinal  cord  carry  the  afferent  impulses. 

What  do  you  mean  by  recurrent  sensibility  ? 

If  after  division  of  a  motor  root  the  peripheral  portion  of  it  be 
stimulated  some  pain  is  felt.  This  is  due  to  what  is  known  as 
recurrent  sensibility,  and  depends  on  the  fact  that  some  of  the  fibres 
of  the  sensory  root,  after  having  joined  the  motor  root,  instead  of 
going  as  usual  to  the  periphery,  revert  and  supply  the  motor  root. 

What  is  the  function  of  the  ganglia  which  occur  on  the 
posterior  roots  of  the  spinal  nerves  ? 
Their  function  is  not  clearly  understood.  There  is  no  evidence 
of  their  being  centres  of  reflex  action,  nor  can  they  be  shown  to 
possess  any  marked  automatic  activity,  but  it  is  supposed  that  they 
preside  over  the  nutrition  of  the  nerve  itself,  for  if  the  roots  be 
cut  off,  that  part  of  the  posterior  root  attached  to  the  cord  de- 
generates, while  the  piece  attached  to  the  ganglion  remains  intact. 
This  is  not  the  case  where  the  anterior  or  motor  root  is  cut,  since 
under  these  circumstances  that  portion  of  the  nerve  next  the  cord 
remains  intact,  while  the  divided  portion  undergoes  degeneration. 
From  this  it  would  appear  that  the  nutrition  of  the  sensory  nerves 
is  governed  by  the  ganglia,  while  that  of  the  motor  nerves  is 
governed  by  centres  in  the  cord  itself. 


118         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  is  the  Ritti-Valli  law  ? 

If  a  nerve  be  separated  from  its  centre,  or  if  the  centre  dies,  the 
excitability  of  the  nerve  is  increased  ;  the  increase  begins  at  the 
central  end  and  travels  toward  the  periphery — the  excitability 
then  falls  rapidly  until  it  disappears  entirely. 

Do  these  changes  take  place  more  rapidly  in  the  central 
or  peripheral  end  ? 
They  take  place  more  rapidly  in  the  central  end.     In  other 
words,  the  peripheral  end  remains  excitable  for  a  longer  time  than 
the  central  end. 


THE  PHYSIOLOGY  OF  THE  CEREBRO- 
SPINAL NERVOUS  SYSTEM. 

The  physiology  of  the  cerebro-spinal  nervous  system  includes 
that  of  the  spinal  cord  and  the  medulla  oblongata,  the  brain,  and 
the  nerves  given  off  from  each  one  of  them,  and  the  functions  of 
the  ganglia  on  those  nerves. 

What  is  the  function  of  the  membranes  of  the  brain  and 
spinal  cord  ? 
The  dura  mater  is  a  tough  membrane,  and  composed  of  bundles 
of  connective  tissue,  whose  function  it  is  to  enclose,  and,  to  a  cer- 
tain extent,  protect  the  nervous  tissue  beneath  it.  The  arachnoid 
is  a  much  more  delicate  membrane,  similar  in  structure  to  the  dura 
mater,  the  function  of  which  is  to  secrete  the  cerebro-spinal  fluid. 
The  pia  mater  consists  of  immense  numbers  of  bloodvessels,  which 
dip  down  and  nourish  the  surface  of  the  brain. 

What  do  you  mean  by  the  neuroglia  ? 

A  special  form  of  connective  tissue  which  supports  the  nerve- 
fibres  and  the  cells  of  the  brain  and  spinal  cord. 

Of  what  does  the  spinal  cord  consist  ? 

It  is  a  cylindriform  column  of  nerve-substance  connected  with 
the  brain  through  the  medium  of  the  medulla  oblongata  and  pons 
Varolii,  and  terminating  in  the  midst  of  the  roots  of  the  many 
nerves  which  form  the  cauda  equina.    It  is  composed  of  white  and 


CEREBRO-SPIN  AL    NERVOUS    SYSTEM.        119 

gray  nervous  matter,  of  which  the  white  is  situated  externally  and 
constitutes  the  chief  portion,  while  the  gray  occupies  its  central 
portion,  and  is  so  arranged  that  on  the  surface  of  a  transverse 
section  it  appears  like  two  somewhat  crescentic  masses,  connected 
together  by  a  narrow  portion  or  isthmus. 

Is  the  spinal  cord  >f  the  same  size  throughout  its  whole 
length  ? 
Nn;  it  varies  greitly.  It  is  very  large  ic  the  middle  and  lower 
part  of  the  cervical  region  and  at  the  lc  .vest  part  of  the  dorsal 
region,  since  at  these  two  points  a  large  number  of  nerve  fibres  are 
given  off. 

Of  what  does  the  white  substance  el  the  spinal  cord  consist? 
Of  nerve  fibres  with  a  medullary  sheath. 

What  is  the  function  of  these  nerve  fibres  ? 
The  transference  of  impulses  from  cell  to  cell. 

Of  what  does  the  gray  matter  consist  ? 

Of  a  dense  network  of  naked  nerve  fibrils  with  numerous  gan- 
glionic cells  scattered  between  them.  The  nerve  fibres  in  this 
substance  also  transmit  impulses  from  cell  to  cell. 

Does  the  white  or  the  gray  substance  contain  the  ganglionic 
cells? 
The  gray  substance. 

What  are  these  cells  called  ? 

Multipolar,  bipolar,  or  unipolar  cells,  for  the  reason  that  they 
possess  processes,  one  or  more  in  number,  which  do  not  divide  in 
the  same  way  as  do  the  interlaced  nerve  fibres. 

What  groups  of  nerve  cells  have  we  in  the  gray  matter  ? 

1.  In  the  anterior  cornua  are  cells  which  are  the  points  of  origin 
for  the  motor  spinal  nerves.     (See  Fig  16.) 

2.  The  tractus  intermedio-lateralis,  a  group  of  nerve  cells  mid- 
way between  the  anterior  and  posterior  cornua,  near  the  external 
surface  of  the  gray  matter.     (See  Fig.  16.) 

3.  The  posterior  vesicular  columns  of  Clarke  and  Stilling  are 
found  in  the  posterior  cornua  near  the  inner  surface.    (See  Fig.  16.) 


120        ESSENTIALS    OF    HUMAN    PHYSIOLOGY". 

4.  The  substantia  gelatinosa  cinerea  of  Rolando  is  scattered 
throughout  the  gray  matter,  but  is  chiefly  found  in  the  posterior 
cornua.     (See  Fig.  16.) 

Fig.  16. 


Anterior  column,  and  anterior 
radicular  zone. 


Antero-lateral  column. 


Posterior  column,  or 
posterior  radicular  zone. 


.Gray  substance. 

Crossed  pyramidal  tract. 
Cerebellar  tract. 
Column  of  Goll. 


Column  of  Burdach. 


Transverse  section  of  the  spinal  cord  at  level  of  the  upper  dorsal  vertebrae. 
(See  scheme  below.) 


Into  how  many  columns  is  the  spinal  cord  divided  ? 

Three  on  each  side.     The  following  scheme  will  illustrate  this 
more  clearly  than  words,  particularly  if  the  figure  is  also  examined. 


1.  Anterior  columns 


2.  Posterior  columns   . 


3.  Lateral  columns 


The  direct  or  uncrossed  pyramidal  tracts,  or 
column  of  TUrck,  or  antero-median  column. 

The  anterior  ground  bundles,  or  anterior  radi- 
cular zones. 

Goll's  column,  or  the  postero-median  column. 
Burdach's  columns,  or  the  posterior  radicular 

zones,  the  posterior  lateral  columns  or  the 

funiculus  cuneatus. 

The  anterior  and  lateral  mixed  paths.    ■ 
The  crossed  pyramidal  paths. 
The  direct  cerebellar  paths. 


CEREBRO-SPIN'AL    NERVOUS    SYSTEM 


121 


Fig.  17. 


Fig.  18. 


py  /mi     p/ 


af  &■    ay- 

Transverse   section   of  spinal   cord   of  Same,  but  in  dorsal  region.    (Afrer 

monkey  ;  lumbar  region.    (After  Ferrier.)  Ferrier.) 


Fig.  19. 
J3?  PS 


Same,  but  in  cervical  region.  (After  Ferrier.) 
A,  Anterior  cornu.  P,  Posterior  cornu.  a,  Anterior  column,  I,  Lateral  column, 
p,  Posterior  column,  ac,  Anterior  commissure,  ae,  External  eel]  group9  ;  and  <n',  in- 
ternal cell  groups,  of  anterior  cornu.  a/,  Anterior  median  fissure,  or,  Anterior  roots. 
.<:,  (Vntral  canal,  /r,  Formatio  reticularis  i7,  Cells  of  the  tractus  intermedio-lateralis. 
re,  Clarke's  vesicular  column,  pc,  Posterior  commissure,  pf,  Pesterior  median  fissure. 
/,m.  Posterior  median  column  (column  of  Goll).  pr,  Posterior  roots,  tg.  Substantlc 
gi-latinosa. 


122         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

Give  the  boundaries  of  each  column. 

The  anterior  column  is  that  tract  which  lies  between  the  anterior 
median  fissure  and  the  point  of  emergence  of  the  anterior  nerve 
roots ;  the  lateral  column  lies  between  the  point  of  emergence  of 
the  anterior  and  posterior  roots,  and  the  posterior  column  between 
the  posterior  roots  and  the  posterior  fissure. 

What  are  Goll's  columns? 

The  posterior  median  columns,  the  functions  of  which  are  not 
as  yet  definitely  known. 

What  are  Turck's  columns  ? 

The  anterior  median  columns,  or  the  direct  pyramidal  tracts. 
They  conduct  impulses  from  the  brain  in  the  same  manner  as  do 
the  lateral  columns. 

The  Functions  of  the  Spinal  Cord. 

In  what  manner  is  conduction  carried  on  by  the  spinal  cord? 
It  carries  the  sensory  impulses  transmitted  to  it  by  the  sensory 
nerves  up  to  the  perceptive  centres  in  the  brain,  and  the  motor 
impulses  from  the  brain  down  to  the  nerves  which  are  distributed 
to  the  muscles. 

Roughly  speaking,  what  portion  of  the  cord  may  be  con- 
sidered motor,  and  what  portion  sensory  ? 
The  anterior  portion  is  motor ;  the  posterior,  sensory. 

What  difference  is  there  in  the  function  of  the  white  and 
gray  matter  ? 

According  to  SchifF,  and  most  physiologists,  the  gray  matter 
transmits  in  all  directions  both  sensory  and  motor  impulses  which 
are  purely  reflex  in  character,  or,  in  other  words,  only  intended  to 
remain  in  the  cord,  while  sensory  impulses  which  are  to  go  to  the 
brain,  or  motor  impulses  which  pass //-owi  the  brain,  must  travel  by 
the  white  matter. 

It  will  be  remembered  that  both  the  anterior  motor  and  the 
posterior  sensory  nerve  roots  do  not  arise  from  the  white  matter, 
but  from  the  horns  of  the  gray. 


CEREBRO-SPINAL   nervous  system.        123 

The  function  of  the  gray  matter  in  the  posterior  horns  is,  there- 
fore, limited  to  the  receipt  and  transmission  of  sensory  impulses 
from  the  periphery  to  the  white  matter,  which  will  conduct  them 
to  the  brain,  or  across  the  cord  to  a  motor  cell  to  complete  a  reflex 
action.1 

The  function  of  the  gray  matter  of  the  anterior  horns  is  limited 
to  the  transmission  of  motor  impulses  from  the  white  matter  to  the 
motor  nerve  trunks,  or  to  the  originating  of  a  reflex  movement. 

What  function  is  supposed  to  be  possessed  by  the  gray 
matter  around  the  central  canal  of  the  spinal  cord  ? 
To  transmit  sensory  impulses   up  to  the   brain  without   their 
having  to  pass  through  the  white  columns. 

In  what  way  can  you  prove,  physiologically,  that  the  anterior 
columns  of  the  cord  are  motor  and  the  posterior  sensory? 
If  the  posterior  columns  be  destroyed,  the  foot  may  be  burnt  off 
but  no  signs  of  pain  are  elicited.     If,  upon  the  other  hand,  the 
anterior  columns    be  destroyed,   burning  of   the   foot  produces 
violent  pain-cries,  but  the  animal  is  unable  to  send  the  impulse 
from  the  brain  to  the  leg  and  draw  it  away  from  the  injury. 
Another  method  is  to  destroy  a  motor  centre  in  the  brain,  and 
some  time  later,  the  animal  being  killed,  tracts  can  be  traced  down- 
ward which  have  undergone  sclerosis  or  atrophy.     Similarly  tracts 
may  be  traced  from  the  periphery  to  the  centres  by  destruction  or 
inflammation  of  a  sensory  nerve.     This  has  not  yet  been  found  in 
he  lateral  sensory  fibres. 

What  is  the  function  of  the  direct  or  uncrossed  pyramidal 
tracts  of   the    anterior  columns   and    the  crossed 
pyramidal  tracts  of  the  lateral  columns  ? 
They  carry  all  the  impulses  from  the  central  convolutions  of  the 

cerebrum,  by  which  voluntary  movements  are  executed. 

Are  the  lateral  columns  solely  efferent  in  function  ? 

No  ;  for  after  destruction  of  the  posterior  columns  of  the  cord, 
burning  of  the  foot  causes  signs  of  pain. 

i  For  definition  of  a  reflex  morement,  • 


124         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  is  the  function  of  the  direct  cerebellar  paths  of  the 
lateral  columns  ? 
They  connect  with  the  cerebellum  directly  by  ascending  fibres, 
which  proceed  through  the  restiform  bodies  from  Clarke's  columns 
of  nerve  cells  in  the  gray  matter.  They  connect  the  posterior  nerve 
roots  of  the  trunk  (not  of  the  extremities)  with  the  cerebellum. 

What  is  the  function  of  the  anterior  ground  bundles  of 

the  anterior  columns,  and  the  anterior  and  lateral 

mixed  paths  of  the  lateral  columns  ? 

They  connect  the  gray  matter  of  the  spinal  cord  with  that  of  the 

medulla,  and  carry  reflex  impulses.     They  also  contain  those  fibres 

which  are  the  direct  continuation  of  the  anterior  spinal   nerve 

roots  which   have  entered   the  gray  matter.      The  anterior  and 

lateral  mixed   paths  of  the   lateral   columns   also   contain   some 

sensory  paths.    This  explains  how  the  afferent  impulses  just  spoken 

of  travel  to  the  medulla. 

What  is  the  function  of  Goll's  column  ? 

It  unites  the  posterior  roots  with  the  gray  nuclei  of  the  posterior 
pyramids,  otherwise  known  as  the  funiculi  gracili,  and  carries 
impulses  centripetaUy . 

By  what  is  the  nutrition  of  these  various  conducting  paths 
governed  ? 
By  nutritive  centres,  in  the  case  of  the  centripetal  tracts,  situated 
in  the  cerebrum.     In  the  centrifugal,  or  motor,  tracts  these  centres 
are  situated  in  the  anterior  cornua  of  the  cord. 

What  classification  can  we  make  in  the  function  of  the 
nervous  centres  in  the  cord? 
Their  functions  can  be  divided  into  conduction,  transference,  reflec- 
tion, and  automatism,  or  the  power  of  originating  impulses  in  them- 
selves. 

Give  an  example  of  conduction  through  a  nerve  centre. 

If  an  impulse  travels  from  a  peripheral  sensory  nerve  to  a  single 
centre  in  the  spinal  cord  reflexly  it  may  produce  contraction  in 
the  muscles  which  are  tributary  to  the  motor  centre  next  to  it. 


CEREBRO-SPIN  AL    NERVOUS    SYSTEM.  125 

This  stimulation,  if  strong  enough,  may  cause  an  impulse  to  travel 
to  all  the  other  centres  in  the  cord,  so  that  general  muscular  move- 
ments may  take  place. 

Give  an  example  of  the  transference  of  nerve  force. 

The  pain  in  the  knee  or  ankle  occurring  during  hip  disease  is  a 
good  example  of  this  condition,  and  is  supposed  to  be  due  to  the 
fact  that  the  sensory  nerves  running  from  the  hip  carry  impulses 
up  to  the  sensory  cells  in  the  spinal  cord,  which  again  transfer  the 
sensation  they  receive  to  sensory  centres  in  direct  communication 
with  the  area  of  the  knee  or  ankle.  Under  these  circumstances 
the  brain  receives  the  impulse  from  the  two  sets  of  fibres  and  mis- 
interprets the  real  cause  of  the  sensory  impulse.  The  impulse, 
under  these  circumstances,  may  be  divided  into  two  portions,  the 
first  of  which  is  the  primary,  and  goes  to  the  brain  directly  from  the 
cells  in  communication  with  the  hip,  while  the  other  is  the 
secondary,  and  is  due  to  the  transference  to  other  centres  of  the 
impulse  before  it  reaches  the  brain.  If  the  primary  and  secondary 
impulses  reach  the  brain  together  the  pain  is  referred  to  both  the 
hip  and  knee. 

What  do  you  mean  by  the  reflexion  of  nerve  force,  or  reflex 
action  ? 
Reflex  action  is  due  to  the  fact  that  an  impulse  travelling  from 
the  periphery  to  the  body  along  the  sensory  nerve  reaches  the 
same  point  at  which  a  sensory  or  receptive  cell  and  a  motor  or  ex- 
pulsive cell  exist  side  by  side.  Under  these  circumstances  the 
sensory  cell  transfers  an  impulse  to  the  motor  cell,  by  conduction, 
which  in  turn  starts  an  impulse  down  along  its  tributary  motor 
nerve,  with  the  result  of  contraction  in  the  muscle  which  it  supplies. 

Give  an  example  of  this. 

If  the  foot  of  a  frog  be  pricked,  the  leg  which  is  pricked,  and  to  a 
certain  extent  the  other  leg,  are  immediately  jerked  away.  That 
this  jerking  away  of  the  leg  is  not  due  to  the  fact  that  the  brain 
desires  to  remove  the  leg  from  the  irritation,  is  proved  by  the  fact 
that  if  the  spinal  cord  be  cut,  thereby  preventing  any  impulses 
from  reaching  the  brain,  reflex  action  is  as  marked  as  if  the  cord 
was  intact. 


126         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  is  Setschenow's  reflex  inhibitory  centre  ? 

A  centre  situated  in  the  upper  portion  of  the  spinal  cord  whose 
function  it  is  to  prevent  excessive  reflex  action.  If  it  were  not  for 
this  centre  the  pricking  of  a  pin  would  cause  but  a  slight  reflex 
contraction  of  the  leg,  while  a  violent  blow  would  send  such  an 
impulse  to  the  reflex  centres  that  a  severe  convulsion  or  tonic 
spasm  might  result.  Under  these  circumstances,  however,  the 
reflex  inhibitory  centre  controls  the  motor  centres  of  the  spinal 
cord  and  prevents  their  sending  out  impulses  which  would  be  too 
violent. 

What  is  automatism  ? 

The  originating,  entirely  independent  of  any  external  cause,  of 
an  impulse  in  a  nerve  cell. 

What  special  centres  have  we  in  the  spinal  cord  ? 
Centres  which  govern  the  bladder  and  genital  organs. 

What  effect  has  irritation  applied  directly  to  the  anterior 
and  lateral  white  columns  ? 
It  produces  muscular  movements  but  no  pain,  and  they  are 
consequently  excitable  but  insensible.1 

Are  the  posterior  columns,  when  irritated,  sensitive   or 
insensitive  ? 
They  are  very  sensitive,   particularly  near  the  origin  of  the 
posterior  roots. 

Is  this  sensibility  due  to  the  presence  of  sensory  nerve 
filaments  belonging  to  these  columns,  or  simply  to 
the  presence  of  the  fibres  of  the  posterior  roots  ? 

It  is  simply  due  to  the  fibres  of  the  roots. 

What  effect  has  section  of  the  antero-lateral  columns  ? 

It  abolishes  all  power  of  voluntary  movement  in  the  lowc 
extremities. 

i  This  has  been  denied  by  Van  Been  and  Schiff,  but  has  been  proved  correct  by  Ficj,, 
Mendelsohn,  Ludwig  and  Woroschilofl,  and  Horsley. 


CEKK  BRO-SI'LVAL    NERVOUS    SYSTEM.  127 

What  effect  has  section  of  the  posterior  column  ? 

The  power  of  muscular  coordination  is  lost.    It  is  these  columns 
which  are  diseased  in  locomotor  ataxia. 

Is  the  transference  of  impulses  stopped  by  this  ? 
No;  because  of  the  sensory  fibres  in  the  lateral  columns. 

Does  the   gray   matter  respond    in    any  way   under   the 
influence  of  direct  stimulation  ? 
No,  it  does  not. 

What  is  the  result  of  a  lesion  of  the  spinal  cord  in  the 
lower  part  of  the  sacral  region? 
There  is  paralysis  of  the  sphincters  of  the  rectum  and  bladder 
and  of  the  accelerator  urinse  and  the  compressor  urethral  muscles. 

What    is  the   result  of   a  lesion  high   up    in  the  sacral 
region  ? 
Paralysis  of  the  muscles  of  the  bladder,  rectum,  and  anus ;  loss 
of  sensation  and  motion  in  the  muscles  of  the  leg,  except  those 
supplied  by  the  anterior  crural  and  obturator  nerves. 

What  is  the  effect  of  a  lesion  of  the  upper  part  of  the 
lumbar  region  ? 
Loss  of  motion  and  sensation  in  both  legs ;  loss  of  power  over 
rectum  and  bladder ;  paralysis  of  the  muscles  of  the  abdominal 
walls.  As  a  result  of  this,  there  is  some  interference  with  respira- 
tion. 

What  effect  has  a  lesion  of  the  cervical  part  of  the  cord  ? 
It  produces  palsy,  as  do  the  other  lesions  named,  with,  in  addi- 
tion, paralysis  of  all  the  intercostal  muscles,  and,  as  a  result,  great 
interference  with  .respiration.  There  is  paralysis  of  the  muscles 
of  the  upper  extremities  except  those  of  the  shoulders.  If  a  lesion 
occurs  at  the  upper  cervical  region,  death  is  instantaneous  from 
respiratory  failure. 


128 


ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 


The  Medulla  Oblongata. 

The  points  to  be  remembered  concerning  this  portion  of  the  nervous 
system  are  as  follows : 

Its  columns  are  continuous  with  those  of  the  spinal  cord,  and 
each  half  of  it  may  be  considered  to  be  divided  into  three  columns 
or  tracts  of  fibres,  in  the  same  manner  as  they  occur  in  the  spinal 
cord. 

What  difference  exists  between  the  columns  here  and  in 
the  cord? 
They  are  more  prominent,  and  separated  from  each  other  by 
deeper  grooves. 

What  are  these  columns  of  the  medulla  called  ? 

Pyramids;  the  anterior  columns  are  called  the  anterior  pyramids, 
those  of  the  posterior  columns  restiform  bodies  and  posterior  pyramids. 


Fig.  20. 


Anterior  median  fissure. 


—        Pyramid. 

Hypoglossal 


Olivary  body. 


Vagus  nerve. 

Membrana  reti- 
culata 

Origin  of  the  tri 
facial. 


Continuation  of 
cerebellar  tracts. 


Posterior  column 


Diagram  showing  cross  section  at  level  of  fourth  ventricle. 


MEDULLA    OBLONGATA.  129 

What  are  the  direct  pyramidal  tracts  ? 

The  anterior  pyramids  which  pass  directly  upward  to  the  cere- 
brum without  crossing  to  the  other  side. 

What  are  the  crossed  pyramidal  tracts? 

Those  fibres  of  the  lateral  columns  which  cross  to  the  opposite 
anterior  pyramid. 

What  is  the  olivary  body  ? 

On  the  outer  side  of  each  anterior  pyramid  is  a  small  oval  mass 
of  gray  matter,  the  olivary  body. 

What  is  the  posterior  pyramid  ? 

A  small  tract  marked  off  from  the  posterior  part  of  the  restiform 
bodies  on  each  side  by  a  slight  groove. 

What  forms  the  fourth  ventricle  ? 

The  restiform  bodies  diverge,  and  by  so  doing  lay  open  a  space— 
the  fourth  ventricle. 

What  is  the  distribution  of  the  fibres  of  the  medulla 
oblongata  ? 
The  anterior  pyramids  receive  fibres  from  the  middle  fibres  of 
the  lateral  columns  of  the  cord,  not  only  from  the  same  side  but 
from  opposite  sides.  In  other  words,  some  of  the  lateral  fibres  of 
the  left  side  enter  the  anterior  pyramid  of  the  right  side  and  vice 
versa.     These  are  the  crossed  pyramidal  tracts  already  mentioned. 

What  is  the  crossing  from  one  side  to  the  other  called  ? 
Decussation. 

After  this  occurs,  what  happens  next  ? 

The  anterior  pyramids  with  their  new  fibres  pass  on  upward, 
the  greater  part  going  through  the  pons  to  the  cerebrum,  while  a 
smaller  part  joins  some  fibres  from  the  olivary  body  forming  the 
olivary  fasciculus  or  fillrt.  Still  another  small  mass  of  fibres  pro- 
ceeds to  the  cerebellum. 

What  course  do  the  fibres  of  the  lateral  columns  pursue  ? 
The  outer  fibres  go  with  the  restiform  tract  to  the  cerebellum, 
the  middle  decussate  to  the  anterior  pyramids  as  al  ready  stated, 


130        ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

and  the  inner  pass  on  to  the  cerebrum  along  the  floor  of  the  fourth 
ventricle. 

What  is  the  direct  cerebellar  tract  ? 

The  outer  fibres  of  the  lateral  columns  first  named. 

Do  the  impulses  of  the  will  which  arise  in  the  brain  pass 
down  each  side  of  the  spinal  cord  directly  and 
produce  contractions  in  muscles  of  the  same  side  ? 

No,  they  do  not.  The  fibres  carrying  these  impulses  cross  each 
other  in  such  a  way  that  impulses  arising  in  the  left  side  of  the 
brain  are  made  manifest  on  the  right  side  of  the  body,  while  those 
arising  in  the  right  side  of  the  brain  are  made  manifest  in  the  left 
side  of  the  body. 

Why  is  this  so  ? 

The  decussation  of  part  of  the  fibres  of  the  anterior  pyramids  of 
the  medulla  transfer  impulses  across  the  cord. 

Does  this  same  transference  of  impulses  take  place  in  the 
sensory  tract,  or,  in  other  words,  is  a  sensation 
occurring  in  the  left  foot  recognized  in  the  right 
hemisphere  of  the  brain  ? 

Yes. 

Does  the  transference  take  place  in  the  medulla  ? 

No,  it  does  not.  The  posterior  fibres  do  not  decussate  in  the 
medulla,  but  Brown-Sequard  has  shown  that  the  crossing  takes 
place  in  the  spinal  cord. 

What  effect  has  section  of  a  lateral  half  of  the  spinal 
cord? 

It  produces  paralysis  of  motion  on  the  injured  side,  but  does  not 
affect  sensation  in  the  least  on  that  side.  On  the  uninjured  side 
motion  is  preserved  but  sensation  lost. 


THE  MEDULLA  OBLONGATA.        131 

Why  is  this  so  I 

Because,  aa  has  already  been  stated,  the  motor  impulses  are  not 
transferred  in  the  cord  but  in  the  medulla,  while  sensory  impulses 
are  transferred  in  the  cord. 

What  is  the  function  of  the  medulla  oblongata  ? 

In  many  ways  it  is  similar  to  that  of  the  spinal  cord  for  it  carries 
on  conduction,  transference,  reflexion,  and  automatism.  It  is  in 
this  portion  of  the  nervous  apparatus  that  the  decussation  of  part 
of  the  fibres  of  the  anterior  cornua  of  the  medulla  takes  place,  ex- 
plaining the  phenomenon  which  has  just  been  mentioned  in  regard 
to  paralysis  occurring  on  the  opposite  side  from  the  lesion. 

What  special  centres  exist  in  the  medulla  oblongata  ? 

First,  the  respiratory  centre^  whose  function  it  is  to  send  out 
those  impulses  which  result  in  respiratory  movements,  and  the 
interference  with  which  causes  great  disorder  of  respiration  or 
death ;  second,  it  contains  the  hypoglossal  nuclei  for  deglutition 
which  send  out  the  impulses  which  produce  the  movements  neces- 
sary to  the  acts  of  swallowing ;  third,  a  centre  for  the  movements 
of  mastication  ;  fourth,  the  chief  vaso-motor  centre  which  governs 
the  bloodvessels  all  over  the  body  (see  Circulation);  fifth,  the 
cardio-inhibitory  centre  for  the  regulation  of  the  movements  of  the 
heart  through  the  pneumogastrics ;  sixth,  the  superior  cilio-spinal 
centres  which  govern  the  movements  of  the  iris1 ;  seventh,  the 
inner  and  outer  nuclei  of  the  special  sense  of  hearing ;  and  eighth, 
the  glosso-pharyngeal  nuclei  for  the  sense  of  taste;  ninth,  the 
centres  for  vomiting.  The  medulla  oblongata  also  gives  rise  from 
its  posterior  surface  and  its  continuation  to  the  cranial  nerves 
from  the  12th  to  the  5th  inclusive.    (See  Figs.  21  and  22.) 

How  do  you  know  that  the  medulla  contains  all  those 
centres  which   are  necessary  for   the  continuance 
of  life  ? 
Because  the  brain  and  cerebellum  can  be  destroyed  and  yet  the 

respiration  and  heart  go  on  unimpaired. 

1  Remember  that  the  inferior  cilio-spinal  centre  acta  thus  also. 


132         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

Fig.  21. 


Diagram  of  posterior  aspect  of  medulla  oblongata  showing  positions  of  the  nuclei  of 
the  cranial  nerves.     (After  Erb  and  Ferrier.) 

v,  Motor  nucleus ;  v',  middle ;  and  v",  inferior  sensory  nucleus  of  the  fifth  nerve ; 
vi,  abducens  nucleus;  vn,  facial  nucleus  ;  vm,  inner,  and  vm',  outer  auditory  nucleus  ; 
vm"  and  vm'",  divisions  of  the  anterior  auditory  nucleus  ;  ix,  glosso-pharyngeal 
nucleus;  x,  vagus  nucleus;  xi,  accessorius  nucleus;  xii,  hypoglossal  nucleus;  1, 
middle  cerebellar  peduncle  ;  2,  superior  cerebellar  peduncle ;  3,  inferior  cerebellar 
peduncle  ;  4,  eminentia  teres ;  5,  stria;  acousticse  ;  6,  ala  cinerea. 


Diagrammatic  representation  of  the  nuclei  of  the  cranial  nerves  as  seen  on  section. 
The  left  half  is  supposed  to  be  removed,  and  the  nuclei  near  the  median  line  are 
shaded  darker  than  the  others.     (After  Erb  and  Ferrier). 

Py.  Pyramidal  tracts.  PyKr.  Decussation  of  the  pyramids.  0.  Olivary  body.  Os. 
Upper  olivary  body.  Roman  numbers  have  same  meaning  as  in  other  cut.  Kz.  Clavate 
nucleus.  Sv.  Boots  of  fifth  nerve.  Bvi.  Roots  of  sixth,  or  abducent  nerve.  Evii. 
Roots  of  facial  nerve. 


THE  MEDULLA  OBLONGATA.        133 

What  is  the  function  of  the  pons  Varolii  ? 

It  contains  a  large  number  of  nerve  fibres  both  transverse  and 
longitudinal,  and  is  a  conductor  of  impressions  from  one  part  of 
the  spinal  axis  to  another.  Concerning  its  functions  as  a  nerve 
centre  little  or  nothing  is  certainly  known. 

What  are  the  functions  of  the  crura  cerebri  ? 

They  are  formed  of  nerve  fibres,  of  which  the  inferior  or  super- 
ficial are  continuous  with  those  of  the  anterior  pyramidal  tracts  of 
the  medulla,  and  the  superior  or  deeper  fibres  with  the  lateral  and 
posterior  pyramidal  tracts,  and  with  the  olivary  fasciculus.  Each 
crus  cerebri  contains  among  its  fibres  a  mass  of  gray  substance 
known  as  the  loci/*  niger.  They  act  principally  as  conducting 
organs.  As  nerve  centres  they  are  probably  connected  with  the 
functions  of  the  oculo-motor  nerves  through  which  are  directed 
the  numerous  movements  of  the  eyeball.  They  are  also  connected 
with  the  coordination  of  other  movements  than  those  of  the  eye. 

What  is  the  result  of  injury  to  the  crus  cerebri  ? 

Hither  rotatory  or  disorderly  movements,  with  loss  of  coordina- 
tion, result. 

What  is  the  function  of  the  corpora  quadrigemina  or  optic 
lobes  ? 

Removal  of  those  bodies  produces  total  loss  of  vision  ;  destruc- 
tion of  one  of  them  produces  blindness  in  the  eye  of  the  opposite 
side.  It  also  produces  rotatory  movements  of  the  body  resembling 
those  occurring  after  division  of  the  crus  cerebri,  save  that  the 
movements  are  slower. 

What  is  the  effect  of  injury  to  these  bodies? 

They  cannot  be  said  to  be  the  centres  of  vision,  but  seem  to  be 
the  centres  of  correlation  between  retinal  impressions  and  oculo- 
motor reactions. 


134 


ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 


What  is  the  function  of  the  corpora  striata  ? 

They  are  centres  of  innervation  for  the  same  movements  as  exist 
in  the  cerebral  cortex,  but  of  a  lower  grade  of  specialization. 

Injury  to  the  corpora  striata  on  one  side  prevents  the  communi- 
cation between  the  will  and  the  muscles  of  the  opposite  half  of  the 
body,  so  that  palsy  results,  or,  in  other  words,  hemiplegia.  The 
corpus  striatum  may,  therefore,  be  considered  as  the  motor  con- 
nection between  the  cerebrum  and  the  crus  cerebri. 

Fig.  23. 


Diagram  of  brain  and  medulla  oblongata,  a,  spinal  cord ;  6,  b,  cerebellum  divided, 
and  above  it  tbe  valve  of  Vieussens  partially  divided  ;  c,  corpora  quadrigemina ;  d,  d, 
optic  thalanii ;  e,  pineal  body;  /,  /,  corpora  striata;  g,  g,  cerebral  bemispheres  in 
section  ;  h,  corpus  callosum  ;  i,  fornix ;  I,  I,  lateral  ventricles ;  3,  third  ventricle ;  4, 
fourth  ventricle  ;  5,  fifth  ventricle,  bounded  on  each  side  by  septum  luciduni.    (Clf.lanb  ) 


What  is  the  function  of  the  optic  thalami  ? 

If  the  optic  thalamus  is  destroyed  on  one  side  sensation  of  the 
opposite  side  of  the  body  is  impaired  or  lost.  It  is,  therefore, 
regarded  as  the  sensory  band  between  the  cerebrum  and  the  crus 
cerebri. 


THE    MEDULLA    OBLONGATA.  135 

What  are  the  functions  of  the  cerebellum  ? 

It  is  absolutely  insensible  to  irritation  and  may  be  cut  away 
without  any  signs  of  pain;  its  removal  from  the  body  or  destruc- 
tion by  disease  is  generally  unaccompanied  by  loss  or  disorder  of 
sensibility.  Animals  from  which  it  is  removed  can  see,  hear,  and 
feel  pain  to  all  appearance  as  perfectly  as  before.  It  governs  the 
coordination  of  movements,  and  while  irritation  of  the  cerebellum 
produces  no  movements  at  all,  remarkable  results  are  produced  by 
removing  part  of  its  substance.  As  portion  after  portion  of  it  is 
cut  away  the  animal  gradually  loses  the  power  of  springing,  walk- 
ing, standing,  or  preserving  its  equilibrium.  If  laid  upon  its  back 
it  cannot  recover  its  normal  posture  but  struggles  to  get  up,  and 
if  a  blow  is  threatened  tries  to  avoid  it,  but  fails  to  do  so. 
According  to  Growers,  the  middle  lobe  of  the  cerebellum  governs 
equilibrium  by  means  of  afferent  fibres  from  the  semicircular 
canals  and  the  ocular  muscles  and  also  the  muscles  of  the  legs. 


What  other  function  has  the  cerebellum  ? 

The  middle  lobe  is  also  very  closely  associated  with  the  vagus, 
and  this  is  the  reason  that  we  are  so  apt  to  have  vomiting  with 
vertigo  or  in  cerebellar  disease. 

What  results  do  we  gain,  therefore,  from  these   experi- 
ments? 

We  know  that  the  cerebellum  has  no  connection  with  volition, 
sensation,  and  memory,  but  merely  has  the  faculty  of  combining 
the  action  of  the  muscles  and  producing  thereby  the  movements 
intended  by  the  higher  nervous  centres.  Remember,  that  the 
influence  of  each  half  of  the  cerebellum  is  directed  to  the  govern- 
ment of  the  opposite  side  of  the  bady,  and  that  both  halves  must 
act  in  unison,  or,  otherwise,  strange  disorders  of  motility  result. 

What  is  the  mean  weight  of  the  brain  ? 

The  mean  weight  of  the  brain  in  man  is  1358  grammes,  in 
woman  it  is  1220  grammes. 


136         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  position  does  the  gray  matter  occupy  in  regard  to 
the  white  ? 

The  gray  matter  forms  the  cortex  and  is  outside  the  white. 

Which  is  the  most  vascular  ? 

The  gray  matter  is  much  more  vascular  than  the  white. 


1, 1,  Medullary  arteries  ;  and  1',  1",  in  groups  between  the  convolutions ;  2,  2,  arteries 
of  the  cortex  cerebri ;  a,  large-meshed  plexus  in  first  layer  ;  5,  closed  plexus  in  middle 
layer ;  c.  more  open  plexus  in  the  gray  matter  next  the  white  substance,  with  its 
vessels  (d).     (Landois.) 


What  two  varieties   of  bloodvessels  do  we  have  in  the 
brain  ? 

The  long  medullary  arteries  which,  as  their  name  implies,  pass 
from  the  pia  mater  to  the  white  matter  through  the  gray,  and  the 
cortical  arteries  which  in  great  part  enter  the  gray  matter  of  the 
cortex  only,  although  some  pass  down  to  the  white  matter. 


THE    MEDULLA    OBLONGATA.  137 

What  difference  is  there  between  these  two  sets  of  arte- 
ries ? 
The  medullary  arteries  are  terminal  and  do  not    anastomose, 
while  the  corticals  do  anastomose  and  are,  therefore,  not  terminal 
arteries. 

What  is  the  physiological  significance  of  this  ? 

A  thrombus  or  embolus  in  one  of  the  medullary  arteries  pro- 
duces a  total  starvation  of  the  area  supplied  by  it,  but  if  such  an 
accident  occurs  to  one  of  the  corticals  then  the  collateral  circula- 
tion prevents  a  total  cutting  off  of  blood  ;  therefore,  we  find  that 
the  most  important  portion  of  the  cerebrum  is  supplied  in  such  a 
way  that  it  is  guarded  against  accident,  while  the  white  matter 
which  is  not  nearly  so  important  is  unprotected.     (See  Fig.  24.) 

What  arrangement  of  bloodvessels  have  we  for  the  nutri- 
tion of  the  rest  of  the  brain  and  the   portions  of 
the  nervous  apparatus  ? 
From  trunks  constituting  the  circle  of  Willis  branches  are  given 

off  which  pass  upward  and  enter  the  brain  to  supply   it   with 

blood. 

Are  these  arteries  terminal,  or  do  they  anastomose  with 
each  other? 
They  are  terminals,  and  do  not  anastomose. 

What  is  the  function  of  the  cerebrum  ? 

The  cerebral  hemispheres  are  the  organs  by  which  perception  is 
carried  on  and  from  which  motor  impulses  are  given  out.  They 
contain  the  organ  of  the  will ;  they  possess  memory,  or  the  means 
of  retaining  impressions  of  sensible  influences;  and  they  are  the 
medium  of  all  the  higher  emotions  and  feelings.  They  carry  on 
intellection  as  is  evidenced  by  imagination,  understanding,  reflec- 
tion, and  judgment. 

How  do  we  know  that  consciousness  depends   upon  the 
action  of  the  cerebral  hemispheres  ? 
If  they  are  injured  in  any  way,  consciousness  is  lost— as,  for 
example,  during  an  apoplectic  fit. 


138         ESSENTIALS    OF    HUMAN"    PHYSIOLOGY 

How  do  we  know  that  it  is  in  the  cerebral  hemispheres 
that  the  intellect  is  situated  ? 

Because  the  higher  the  intellect  is  the  greater  development  is 
possessed  by  the  brain,  and  because  destruction  of  the  cerebrum 
stops  intellection.  Congenital  and  other  morbid  conditions  of 
the  hemispheres  always  produce  disorders  of  the  intellect. 

What  effect  has  the  extirpation  of  the  cerebrum  ? 

After  the  removal  of  both  cerebral  hemispheres  in  animals, 
every  voluntary  impulse,  every  conscious  impression,  and  every 
sensory  perception  ceases,  but  the  maintenance  of  the  equilibrium 
and  all  the  mechanical  movements  of  the  body  are  preserved. 

What  example  of  this  can  you  give  ? 

A  frog  with  its  cerebrum  removed  retains  its  power  of  main- 
taining its  equilibrium.  It  can  sit,  spring,  or  execute  complicated 
movements  which  are  coordinated,  and  when  it  is  placed  upon  its 
back  immediately  turns  right  side  up  again. 

What  is  the  purpose  of  the  convolutions  ? 

In  order  to  give  a  greater  surface  for  the  spreading  of  the  cells 
in  the  cortex  without  making  the  brain  so  large  that  the  skull 
would  be  out  of  proportion  to  the  body. 

What  do  you  mean  by  cerebral  localization  ? 

The  determination  of  the  areas  in  the  cerebral  hemispheres 
governing  various  portions  or  functions  in  the  body. 

Where  is  the  speech  centre  located  in  the  cerebrum  ? 
In  the  third  frontal  convolution  and  the  Island  of  Reil. 

On  which  side   of  the  brain  is  the    speech    centre    best 
developed  ? 

The  left  side. 


THE    MEDULLA    OBLONGATA.  139 

What  are  these  areas? 

The  surface  of  the  cerebrum  may  be  divided  into  three  sections 
— anterior,  middle,  and  posterior.  The  anterior  lobes  contain  the 
cells  for  intellection,  the  middle  areas  the  cells  for  motion,  and 

the  posterior  lobes  those  for  sensation  or  perception. 

As  an  example  of  some  of  the  motor  centres,  give  the  area 
for  the  arm  and  leg. 
Stimulation  of  the  upper  extremity  of  the  ascending  parietal 
and  ascending  frontal  convolution  causes  movement  of  leg,  while 
stimulation  of  these  two  areas  lower  down  causes  movements  of 
the  arm. 

What  is  the  relative  position  of  the  chief  centres  in  the 
brain  ? 

It  is  a  fact  that  the  centres  which  govern  the  more  massive  parts 
and  which  govern  the  lower  regions  of  the  body  are  high  up  in 
the  brain,  while  the  centres  for  the  control  of  the  face  and  arm, 
for  example,  are  lower  down  on  the  surface  of  the  cortex. 

What  portion  of  the  brain  perceives  pain  ? 

Horsley  has  shown  that  destruction  of  the  gyrus  fornicatus 
prevents  the  perception  of  pain. 

In  what  two  ways  are  these  impulses  carried  to  the  lower 
portions  of  the  nervous  system  ? 
From  all  this  area  radiating  fibres  converge  to  the  base  of  the- 
brain,  where  some  of  them  pass  through  the  corpora  striata  and 
its  three  nuclei  (the  caudate,   lenticular,  and  taeniform),  while 
others  pass  through  the  internal  capsule. 

What  course  do  these  fibres  now  take  ? 

After  leaving  the  internal  capsule  these  fibres  once  more  meet 
some  of  those  fibres  which  passed  through  the  nuclei  of  the  cor- 
pora striata  and  form  the  crustse  of  the  crura  cerebri,  which  con- 
tinuing downward  through  the  pons  Varolii  emerge  from  its 
posterior  and  lower  border  in  the  form  of  the  anterior  pyramids 
of  the  medulla  oblongata. 


140         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  course  do  centripetal  impulses  take  to  get  to  this 
portion  of  the  brain  ? 

When  the  sensory  fibres  of  the  spinal  cord  reach  the  medulla 
oblongata  they  pass  up  on  either  side  of  the  motor  nuclei  to  form 

Fig.  25. 


Diagram  of  some  of  the  paths  taken  by  uerve  impulses  in  the  brain  and  spinal  cord. 
;.  Gray  substance  of  cerebral  cortex,  c1.  Gray  substance  of  cerebellum,  cr.  Cranial 
nerves,  some  afferent  and  some  efferent.  M.  Motor  (efferent)  spinal  nerves.  S.  Sensory 
(afferent)  spinal  nerves.     (Yeo.) 

the  tegmenta,  and  to  become  connected  with  the  optic  thalami, 
corpora  geniculata,  and  corpora  quadrigemina.  From  these 
ganglia  radiating  fibres  pass  to  the  receptive  areas  of  the  brain. 


THE    CRANIAL    NERVES.  141 


THE  CRANIAL  NERVES. 

It  will  be  remembered  that,  according  to  most  anatomists,  the 
cranial  nerves  are  divided  into  twelve  pairs. 

1.  What  is  the  function  of  the  olfactory  nerve  ? 

It  is  the  nerve  of  special  sense  by  which  odors  are  distinguished; 
in  other  words,  it  is  the  nerve  of  smell.  It  is  distributed  to  the 
mucous  membrane  of  the  nose,  and  arises  superficially  from  the 
lower  part  of  the  frontal  lobe  in  advance  of  the  anterior  perforated 
-pace,  passing  through  the  cribriform  plate  of  the  ethmoid  bone. 

2.  What  is  the  function  of  the  optic  nerve  ? 

It  is  the  nerve  of  sight,  and  is  distributed  to  the  retina  of  the 
eye.  It  arises  superficially  from  the  geniculate  and  quadrigeminal 
bodies  and  thalamus,  and  passes  out  through  the  optic  foramen  of 
the  orbit.     It  conveys  no  other  impulses  than  those  of  sight. 

What  is  the  effect  of  division  of  one  of  the  optic  nerves  ? 
It  produces  complete  blindness  in  the  eye  of  the  corresponding 
side. 

What  is  the  effect  of  division  of  the  optic  tract  ? 

It  produces  loss  of  sight  in  the  outer  half  of  the  eye  of  the  same 
side,  and  of  the  inner  half  of  the  eye  of  the  opposite  side. 

What  is  the  effect  of  injury  to  the  anterior  part  of  the 
optic  chiasm  ? 

It  causes  blindness  in  the  inner  half  of  both  eyes. 

3.  What  is  the  function  of  the  oculo-motor  nerve  ? 

It  is  the  motor  nerve  of  the  levator  palpebrarum,  the  superior, 
internal,  and  inferior  rectus,  and  the  inferior  oblique  muscle  of  the 
eye.  Its  superficial  origin  is  the  inner  side  of  the  cerebral  crus, 
and  it  finds  its  exit  from  the  sphenoidal  foramen.  It  also  supplies 
filaments  to  the  ciliary  ganglia  from  which  the  ciliary  nerves 
arise,  which  enter  the  eyeball  and  are  distributed  to  the  circular 
fibres  of  the  iris  and  the  ciliary  muscle.  It  governs  the  accommo- 
dation of  the  eye. 


142       ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  effect  has  stimulation  of  the  oculo-motor  on  the 
pupil  ? 
It  causes  contraction  of  the  pupil,  internal  strabismus,  and  mus- 
cular movements  of  the  eye,  but  no  pain.  Section  of  the  nerve  is 
followed  by  ptosis,  or  drooping  of  the  upper  eyelid,  internal  stra- 
bismus, due  to  the  supposed  action  of  the  external  rectus  muscle, 
and  paralysis  of  the  accommodation  of  the  eye. 

4.  What  is  the  function  of  the  pathetic  nerve  ? 

It  governs  the  movements  of  the  eyeball  so  far  as  those  are  con- 
cerned which  are  produced  by  the  action  of  the  superior  oblique 
muscle ;  it  arises  from  the  valve  of  Vieussens  and  passes  through 
the  sphenoidal  foramen. 

5    What  is  the  function  of  the  trifacial  nerve  ? 

It  is  a  nerve  of  sensation,  motion,  and  taste.  It  arises  from  the 
side  of  the  pons  by  a  smaller  motor  and  a  larger  sensory  root,  and 
is  divided  into  three  divisions,  the  first  of  which  supplies  the 
conjunctiva,  the  lachrymal  gland,  the  eyeball,  the  upper  eyelid, 
the  integument  of  the  forehead,  and  the  mucous  membrane  and 
integument  of  the  nose.  The  second  division  supplies  the  lower 
lid  and  conjunctiva,  the  temple,  upper  lip,  nose,  cheeks,  and  teeth 
of  the  upper  jaw.  These  two  divisions  are  purely  sensory.  The 
third  division  supplies  the  muscles  and  skin  of  the  lower  part  of 
the  face,  the  muscles  of  mastication,  the  teeth  in  the  lower  jaw,  the 
tongue,  the  parotid  gland,  and  the  auricle  of  the  ear.  This  di- 
vision contains  motor,  sensory,  and  other  filaments  which  carry 
the  sense  of  taste. 

What  is  the  effect  of  irritation  of  the  larger  root  of  the 
trifacial  nerve  ? 
It  produces  marked  evidence  of  pain,  which  is  always  felt  in  the 
periphery  of  the  nerve,  since  it  will  be  remembered  that  pain 
arising  at  the  origin  of  a  sensory  nerve  is  always  referred  to  its 
peripheral  filaments.  Irritation  of  the  small  root  produces  move- 
ments of  the  muscles  of  mastication,  whilst  section  of  this  root 
causes  paralysis  of  these  muscles.     Section  of  the  large  root  is 

1  For  medullary  origin  of  all  the  rest  of  the  cranial  nerves,  see  page  121. 


THE    CRANIAL    NERVES.  143 

followed  by  a  complete  abolition  of  sensibility  in  the  head  and 
face,  but  no  disturbance  of  motion. 

6.  What  is  the  function  of  the  abducent  or  sixth  pair  of 

nerves  ? 
Motion,  which  results  in  turning  the  eyeball  outward.  They 
arise  from  the  anterior  pyramids,  and  supply  the  external  rectus 
muscle  of  the  eye.  Stimulation  of  this  nerve  causes  outward 
rotation  of  the  eyeball,  while  paralysis  of  it  causes  internal  stra- 
bismus. 

7.  What  is  the  function  of  the  facial  nerve  ? 

It  supplies  the  motor  filaments  of  the  muscles  of  the  ear,  scalp, 
and  face — platysma,  digastric,  and  stylohyoid  muscles— and  arises 
between  the  olivary  and  restiform  bodies.  It  finds  its  exit  through 
the  internal  auditory  meatus,  the  facial  canal,  and  the  stylo- 
mastoid foramen. 

What  is  the  peculiarity  of  the  facial  nerve? 

It  is  a  motor  nerve  in  its  origin,  but  in  its  course  receives  sensory 
filaments  from  the  fifth  pair  and  the  pneumogastric.  Irritation  of 
the  facial  produces  muscular  contractions,  while  division  produces 
paralysis  of  the  muscles  of  the  face.  Remember,  that  it  is  this 
nerve  which  gives  off  the  chorda  tympani,  that  branch  which 
supplies  the  bloodvessels  and  secretion  of  the  sublingual  and  sub- 
maxillary glands  and  the  sense  of  taste  in  the  anterior  two-thirds 
of  the  tongue. 

8.  What  is  the  function  of  the  auditory  nerve  ? 

It  governs  the  sense  of  hearing,  conducting  the  impulses  from 
the  exterior  to  the  brain.  It  rises  in  the  floor  of  the  fourth  ven- 
tricle, and  is  distributed  to  the  labyrinth  of  the  ear.  Destruction 
of  this  nerve  produces  deafness. 

9.  What  is  the  function  of  the  glossopharyngeal  nerve  ? 
It  governs  the  sensibility  of  the  pharynx,  and  therefore  influences 

taste.     It  has  also  motor  filaments  which  pass  to  the  root  of  the 
tongue,  the  tonsils,  the  soft  palate,  the  pharynx,  and  the  tympanum. 


144       ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

10.  "What  is  the  function  of  the  pneumogastric  or  vagus 

nerve  ? 

It  is  chiefly  made  up  of  sensory  filaments  which  anastomose 
with  motor  filaments  from  other  sources.  It  influences  deglutition, 
the  action  of  the  heart,  the  circulatory  and  respiratory  systems, 
the  voice,  and  the  stomach.  It  arises  from  the  fore  part  of  the 
restiform  body  and  the  vagal  nucleus  of  the  floor  of  the  fourth 
ventricle.  The  functions  of  its  branches  have  been  considered 
when  studying  the  circulation,  respiration,  etc. 

11.  What  is  the  function  of  the  spinal  accessory  nerve  ? 

It  is  made  up  of  motor  filaments,  some  of  which  pass  to  the 
vagus  nerve,  while  others  supply  the  stern o-mastoid  and  trapezius 
muscles.  It  arises  from  the  lateral  columns  of  the  spinal  cord  and 
the  gray  substance  within.  It  will  be  remembered  that  it  consists 
of  two  parts,  a  smaller  accessory  root  whose  deep  origin  is  in  a 
nucleus  of  gray  matter  at  the  back  of  the  medulla  below  the  origin 
of  the  vagus,  and  a  large  spinal  root  from  the  lateral  columns  of 
the  cord. 

What  is  the  effect  of  destruction  of  its  medullary  root? 

It  produces  paralysis  of  the  laryngeal  muscles,  resulting  in 
aphonia,  and  impairs  the  action  of  the  muscles  of  deglutition. 
Irritation  of  the  spinal  root  produces  contractions  of  the  trapezius 
and  sterno-mastoid  muscles,  but  section  of  this  branch  does  not 
produce  absolute  palsy  in  these  muscles,  since  they  are  supplied 
by  motor  filaments  from  elsewhere. 

12.  What  is  the  function  of  the  hypoglossal  or  sublingual 

nerve  ? 

Its  function  is  motor  and  it  governs  all  the  movements  of  the 
tongue,  influences  mastication,  deglutition,  and  articulate  lauguage. 
It  rises  from  the  anterior  pyramid,  the  olivary  body,  and  the 
hypoglossal  neucleus.  Irritation  of  it  produces  convulsive  move- 
ments of  the  tongue,  while  division  of  it  abolishes  all  these  move- 
ments and  interferes  considerably  with  deglutition  ;  articulation 
is  considerably  impaired,  and  mastication  is  performed  with  diffi- 
culty from  inability  to  retain  the  food  between  the  teeth. 


THE    SPECIAL    SENSES.  145 


THE    SPECIAL    SENSES. 

What  do  you  mean  by  the  term    '  nerves  of  special  sense  "1 
Those  aerves  which  carry,  as  do  sensory  nerves,  impulses  from 

the  periphery  to  those  centres  in  the  brain  which  may  perceive 
and  interpret  them,  and  which  differ  from  the  ordinary  sensory 

nerves  in  that,  as  a  general  rule,  the  impulses  are  not  the  result  of 
ordinary  stimulation  by  contact,  but  of  one  special  form  of  irrita- 
tion. As  an  example  of  this  the  optic  nerve  appreciates  light,  yet 
light  can  never  be  said  to  produce  activity  of  the  nervous  proto- 
plasm by  contact;  nor  do  the  vibrations  of  air  produced  by  sound 
cause  any  impulses  to  travel  along  any  sensory  nerves  save  the 
auditory ;  neither  can  we  say  that  the  olfactory  nerves  are  stimu- 
lated mechanically  by  the  presence  of  substances  so  small  that 
they  cannot  be  distinguished  by  spectrum  analysis,  but  which, 
nevertheless,  are  perceived  by  the  nostrils ;  this  is  the  reason  why 
each  one  of  the  nerves  carrying  the  impressions  of  sight,  smell, 
taste,  or  sound,  are  called  special,  since  each  one  of  them  can 
transmit  but  one  variety  of  impulse. 

Do  the  nerves  which  carry  these  impulses  of  special  sense 
differ  from    other  nerves   in   their   structure    and 
ordinary  capabilities  ? 
No;  they  differ  in  no  way  at  all  from  ordinary  afferent  nerves, 

with  one  or  two  exceptions. 

Is  the  sensation  recognized  at  the  point  at  which  the  cause 
exists,  or  by  the  special  centres  in  the  brain  ? 
It  is  recognized  in  the  centre,  but,  as  has  been  stated  before, 
impulses  in  sensory  nerves  are  always  referred  to  the  periphery, 
and,  therefore,  we  are  accustomed  to  say  that  we  feel  the  burn  or 
other  injury  at  the  spot  where  it  occurs. 

By  what  means  is  this  peculiar   condition  in  regard  to 
sensation  governed  ? 
It  is  solely  governed  by  the  mind  itself,  which  has  been  taught 
to  do  this  as  the  result  of  education,  experience,  and  habit,  acquired 
by  a  long  series  of  unconscious  experiments  in  early  youth. 

10 


146      ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  is  necessarily  present  for  a  complete  special  sense 
apparatus  ? 
First,  a  special  nerve  ending,  only  capable  of  being  excited  by 
special  forms  of  stimuli ;  second,  an  afferent  nerve  to  conduct  the 
impulse  from  the  special  end  organ  to  the  nerve  centre;  third, 
nerve  cells  forming  a  centre,  which  is  capable  of  translating  the 
impulse  received  into  a  sensation  and  of  referring  that  sensation  to 
some  local  point ;  fourth,  associated  nerve  centres  capable  of  per- 
ceiving sensations,  forming  ideas,  and  drawing  conclusions  there- 
from, with  the  object  of  determining  the  position,  character,  and 
intensity  of  the  external  influence. 

The  Sensibility  of  the  Skin. 

Those  impulses  which  are  received  through  the  skin  are  obtained 
through  the  sense  of  touch. 

Into  how  many  divisions  is  this  sense  of  touch  subdivided? 

First,  tactile  sensibility,  by  means  of  which  we  appreciate  the 
slightest  touch  and  recognize  the  exact  point  at  which  the  skin 
receives  the  impulse.  Second,  the  sense  of  pressure,  by  which  we  are 
enabled  to  judge  of  the  compression  which  is  being  exerted  on  a 
certain  area ;  this  sense,  however,  is  by  no  means  so  well  developed 
as  the  tactile  sense.  Tlvlrd,  the  sense  of  temperature,  by  which  we 
are  enabled  to  determine  whether  an  object  is  hot  or  cold.  This 
sense,  also,  is  not  perfectly  developed,  since  for  a  moment  we  are 
unable  to  determine  whether  an  object  is  hot  or  cold  unless  the 
eye  or  other  special  sense  aids  us. 

"What  is  the  object  of  tactile  sensibility? 

In  order  that  we  may  judge  of  the  position,  character,  and  shape 
of  bodies. 

Is  tactile  sensibility  exceedingly  important  to  the  animal 
organism  ? 
Very  important,  since  without  it  nothing  could  be  held  firmly 
in  the  hand,  and  all  the  movements  of  the  body  would  be  seriously 
interfered  with. 


THE    SENSE    OF    TASTE.  1  17 

In  what  way  are  the  nerves  arranged  for  tactile  sensi- 
bility ? 
The  sensory  nerves  running  to  the  skin  are  endowed  with 
endings  of  various  forms  according  to  their  function  ;  these  forms 
are  divided  into  five  varieties :  First,  the  touch  corpuscles,  which 
are  egg-shaped  bodies  situated  in  the  papillae  of  the  true  skin, 
directly  under  the  epithelial  cells  of  the  rete  mucosum ;  they  vary 
in  siz,e  c  msiderably,  according  to  the  amount  of  work  which  they 
:irc  forced  to  perform;  in  these  the  axis-cylinder  of  the  nerve 
ends.  Second,  the  end  bulbs,  which  are  smaller  than  the  last  and 
differ  from  them  in  that  they  are  only  distributed  to  localized 
areas;  they  are  made  up  of  a  little  vesicle  containing  fluid  in 
which  the  axis-cylinder  terminates,  the  wall  of  the  vesicle  joining 
the  sheath  of  the  nerve.  Third,  touch  ce/ls,  which  differ  from  the 
others  in  that  they  exist  in  the  deeper  layer  of  the  epiderm. 
Fourth,  free  nerve  endings,  which  occur  on  the  surface  of  the  epi- 
thelium of  mucous  membranes.  Fifth,  Pacinian  corpuscles,  which 
are  ovoid  bodies  made  up  of  concentric  layers  of  varying  con- 
sistence, with  a  collection  of  fluid  in  the  centre,  in  which  the  axis- 
cylinder  ends. 

The  Sense  of  Taste. 

In  what  way  is  taste  produced  ? 

By  the  contact  of  sapid  substances  with  the  endings  of  the 
gustatory  nerves  of  the  tongue  in  the  various  papillae. 

What  are  these  papillae  sometimes  called  ? 
"Taste  buds"  or  "  taste  goblets." 

Is  it  possible  to  taste  a  dry  substance  ? 

No;  when  a  dry  substance  is  placed  on  the  tongue  the  moisture 
dissolves  or  moistens  at  least  some  of  it. 

What  proof  have  we  that  this  is  so? 

If  the  tongue  be  thoroughly  dried  no  taste  is  perceived. 

Where  is  the  chief  sense  of  taste  situated  ? 
In  the  tongue. 


148       ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  other  surfaces  aid  the  tongue  in  tasting  ? 

The  soft  palate  and  its  arches,  the  uvula,  tonsils,  and  upper 
pharynx.     The  hard  palate  has  little  taste  power. 

What  is  the  nerve  supply  of  the  back  part  of  the  tongue? 

The  glosso-pharyngeal. 

What  is  the  nerve  supply  of  the  tip  of  the  tongue  ? 
The  lingual  branch  of  the  trifacial  nerve. 

What  portion  of  the  tongue  perceives  taste  the  best  ? 

The  back  portion.  The  tip  and  middle  of  the  tongue  are  not  so 
well  endowed  with  nerves.1  The  sense  of  smell  aids  the  sense  of 
taste  when  eating.  If  the  nostrils  be  closed  and  the  eyes  shut  no 
distinction  can  be  exercised  between  a  piece  of  apple,  potato,  or 
onion  on  the  tongue. 

Do  certain  areas  of  the  tongue  taste  certain  bodies  ? 

Yes.  The  sulphate  of  quinine  is  scarcely  noticed  at  the  tip,  at 
the  back  it  is  very  well  perceived.  Sugar,  on  the  other  hand,  is 
best  tasted  on  the  tip  of  the  tongue. 

The  Sense  of  Smell. 

How  is  the  sense  of  smell  excited  ? 

By  fine  bodies  floating  in  the  atmosphere. 

What  effect  on  smelling  has  drying  of  the  nasal  mucous 
membrane  ? 

It  impairs  the  power  of  perceiving  odors  very  greatly. 

What  is  the  object  of  sniffing  ? 

In  order  to  draw  over  the  nerve  endings  a  current  of  air  con- 
taining the  odor. 

In  what  way  are  the  olfactory  nerves  arranged  ? 

Most  of  these  nerves  are  distributed  to  the  mucous  membrane  of 
the  middle  and  upper  meatus  of  the  nose.     The  mucous  membrane 

1  For  the  muscular  movements  of  the  tongue,  see  Mastication. 


THE    SENSE    OF    SIGHT.  L49 

in  this  area  is  not  covered  by  motile  cilia  such  as  are  found  in  the 
rest  of  the  nasal  cavity;  it  is  less  vascular  and  of  a  peculiar 
yellow  hue.  The  extreme  delicacy  of  smell  can  best  be  understood 
when  we  remember  that  Valentin  has  estimated  that  two-millionths 
of  a  milligram  of  musk  is  sufficient  to  excite  the  olfactory  nerves 
if  man.     In  other  animals  this  sense  is  even  more  acute. 


The  Sense  of  Sight. 

The  Eye  and  its  Coverings 

What  is  the  function  of  the  eyelids  ? 

To  protect  the  eyeballs,  and  to  distribute  moisture  over  them 
constantly,  thereby  preventing  drying. 

How  are  they  formed  ? 

They  are  movable  folds  of  skin,  each  of  which  is  kept  in  shape 
by  a  thin  plate  of  yellow  elastic  tissue. 

What  is  the  function  of  the  eyelashes  ? 

To  prevent  the  entrance  of  foreign  bodies,  especially  when  the 
lids  are  half  closed. 

In  what  way  do  they  differ  from  ordinary  hairy  growths  ? 

They  possess  tactile  sensibility,  which  causes,  reflex lv,  the  lids 
to  close  tightly  when  a  foreign  body  touches  them. 

What  is  the  purpose  of  the  Meibomian  glands  along  the  edges 
of  the  lids? 
To  lubricate  them,  and  prevent  irritation  from  the  tears. 

In  what  portion  of  the  orbit  is  the  lachrymal  gland  placed  ? 
In  the  upper  and  outer  angle. 

What  is  the  use  of  the  lachrymal  gland  ? 

To  secrete  liquid,  which  will  lubricate  and  keep  the  eve  moist. 
When  an  excessive  secretion  takes  place  it  runs  over  the  lower 
lids,  in  the  form  of  tears. 

On  what  side  of  the  orbit  does  the  lachrymal  secretion  escape  ? 
On  the  inner  side,  through  thepuncta  lachrymalia,  one  of  which 


150      ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

exists  in  each  lid ;  thence  it  passes  into  the  lachrymal  sac,  and 
from  there  through  the  nasal  ducts  into  the  nose. 

What  function  has  the  lower  eyelid  which  is  not  possessed 
by  the  upper  lid? 

It  acts  as  a  gutter  along  which  an  excess  of  the  tears  may  flow ; 
when  one  cries  the  gutter  overflows. 

What  is  the  function  of  the  orbicularis  palpebrarum  muscle, 
and  what  is  its  nerve  supply  ? 

It  closes  the  eye,  and  is  supplied  by  the  facial  nerve. 

What  muscle  opens  the  eye  ? 

The  upper  lid  is  raised  by  the  levator  palpebrarum  superior, 
which  is  supplied  by  the  o"culo-motor  nerve. 

In  what  way  does  the  ending  of  the  optic  nerve  differ  from 
any  other  sensory  nerve  ? 

It  is  enclosed  in  a  specially  arranged  organ,  the  eyeball. 

What  is  the  object  of  the  eyeball? 

For  the  purpose  of  so  directing  the  rays  of  light  that  they  strike 
in  a  certain  way  upon  the  peripheral  optic  filaments.  It  also  pro- 
tects the  nerve  filaments  from  all  contact  with  external  conditions, 
except  light. 

What  is  the  only  stimulus  which  ordinarily  excites  the  optic 
nerve  ? 

Light. 

What  is  the  purpose  of  the  movements  of  the  eyeball? 

In  order  that  objects  may  be  brought  within  the  range  of  vision 
without  movements  of  the  head. 

If  electrical,  mechanical,  or  other  stimuli  be  applied  to  the 
optic  nerve,  what  sensations  will  they  produce  ? 
Light  is  the  only  thing  appreciated. 

What  is  the  function  of  the  sclerotic  coat  of  the  eye  ? 

It  gives  shape  and  protection  to  the  organ. 

Is  the  sclerotic  coat  continuous  all  over  the  eyeball? 

No,  it  is  not ;  for  at  the  anterior  portion  is  a  window-like  open- 
ing, known  as  the  cornea,  through  which  the  rays  of  light  pass. 


THE    SENSE    OF    SIGHT.  151 

What  is  the  function  of  the  cornea  ? 

It  permits  light  to  enter  the  eye  in  much  the  same  manner  as  a 
window-pane  lets  light  into  a  room,  and  it  also  effects  very  mark- 
edly refraction  of  the  rays  of  light. 

What  peculiar  bodies  have  we  in  the  cornea  which  move 
about  ? 
The  corneal  corpuscles,  which  resemble  amoebae  in  their  move- 
ments. 

Does  the  cornea  possess  nerves  and  bloodvessels  ? 
Only  nerves,  which  are  partly  sensory  in  function. 

From  what  are  these  nerves  derived  ? 
From  the  long  and  short  ciliary  nerves. 

What  change  takes  place  in  these  nerves  as  they  enter  the 
cornea  ? 
They  enter  the  cornea  as  medullated  nerve  fibres,  but  the  myelin 
soon  disappears  and  leaves  the  naked  axis  cylinder. 

In  what  way,  then,  is  it  nourished  ? 
By  absorption  from  the  bloodvessels  at  the  corneal  margin. 

What  is  the  function  of  the  choroid  coat  ? 

<  hving  to  its  black,  pigmented  connective  tissue  cells,  it  prevents 
the  transmission  of  all  light  from  the  exterior,  save  by  the  corneal 
opening,  and  prevents  reflections  from  side  to  side.  It  is  this  coat 
which  lacks  pigment  in  albinoes  and  nocturnal  animals,  and  its 
absence  prevents  good  vision  in  the  daytime. 

What  are  the  ciliary  processes  ? 

They  are  highly  vascular  folds  of  the  choroid,  occurring  near 
the  edge  of  the  cornea. 

What  is  the  function  of  the  ciliary  muscle  ? 

It  attaches  the  choroid  to  the  sclerotic  coat,  governs  the  diametei 
and  shape  of  the  crystalline  lens,  and  governs  accommodation. 


152         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  is  the  function  of  the  iris  ? 

It  is  a  circular  membranous  diaphragm  provided  with  a  central 
aperture,  the  pupil,  and  regulates  the  amount  of  light  entering 
the  eye.  It  contains  two  sets  of  muscular  fibres,  circular  and 
radiating. 

What  are  the  functions  of  these  two  sets  of   muscular 
fibres  ? 

The  radiating  fibres  dilate  the  pupil,  the  circular  fibres  contract  it. 

What  is  the  object  of  this  pupillary  movement  ? 
The  regulation  of  the  amount  of  light  entering  the  eye. 

Have  the  vessels  of  the  choroid  any  intimate  connection 
with  the  nutrition  of  the  eye  ? 

Yes. 

Describe  these  bloodvessels. 

The  arteries  are  the  short  posterior  ciliary  arteries,  which  are 
about  twenty  in  number  and  perforate  the  sclerotic  near  the  optic 
nerve.  They  terminate  in  the  vascular  network  of  the  chorio- 
capillaris,  which  reaches  as  far  as  the  ora  serrata.  The  long  posterior 
ciliary  arteries  lie  on  the  nasal  and  temporal  side  of  the  eye;  they 
run  to  the  ciliary  part  of  the  choroid  and  penetrate  the  iris,  helping 
to  form  the  circulus  arteriosus  iridis  major.  The  anterior  ciliary 
arteries,  which  arise  from  the  muscular  branches,  perforate  the 
sclerotic  coat  anteriorly  and  give  branches  to  the  choroid  and  iris. 

What  are  the  veins,  and  what  is  their  function  1 

The  anterior  ciliary  veins  receive  the  blood  from  the  anterior 
part  of  the  eyeball  and  carry  it  outward ;  they  do  not  receive  any 
blood  from  the  iris. 

In  what  way  does  the  blood  from  the  iris  pass  out  of  the 
eye? 
The  venous  plexus  of  the  ciliary  processes  receives  the  blood 
from  the  iris  and  passes  it  backward  to  the  choroidal  veins. 


THE    SENSE    OF    SIGHT.  153 

What  arrangement  have  we  on  the  posterior  surface  of  the 
iris  to  prevent  the  transmission  of  light  through  it? 
A  layer  of  dark  pigment. 

What  is  the  nerve  supply  of  the  circular  fibres  of  the  iris? 
The  oculo-motor. 

What  is  the  nerve  supply  of  radiating  or  dilating  fibres  ? 
The  trifacial  and  sympathetic. 

Why  does  the  pupil  contract  when  we  are  looking  at  near 
objects,  but  dilate  for  objects  which  are  far  away  ? 
When  an  object  is  near,  the  rays  of  light  are  so  near  together 
that  they  enter  through  a  small  opening ;  when  it  is  far  off  the 
pupil  dilates,  in  order  to  let  all  the  rays  in  that  it  can  to  make  the 
image  more  distinct. 

What  is  the  function  of  the  retina  ? 

Lying  next  to  the  choroid  coat  the  retina  is  formed  by  the 
expansion  of  the  optic  nerve,  and  it  is  this  membrane  which 
receives  tbe  impression  of  light. 

What  is  the  chemical  reaction  of  the  retina  ? 

When  fresh  it  is  acid  in  light,  but  it  is  alkaline  in  darkness. 

In  what  way  do  the  nerve  filaments  end  in  the  retina  ? 
In  the  rods  and  cones. 

Which  of  these  is  most  highly  developed  in  man  ? 
The  rods. 

What  do  you  mean  by  the  blind  spot  ? 

A  small  point  in  the  retina  on  which,  when  light  falls,  no 
impulse  is  produced  ;  it  is  the  point  of  entrance  of  the  optic  nerve. 

What  do  you  mean  by  the  macula  lutea  ? 

The  point  at  which  rays  of  light  produce  the  greatest  visual 
impression.     It  is  exactly  in  the  centre  of  the  retina. 


154        ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

Are  the  rods  or  the  cones  in  greater  number  here? 
The  cones. 

What  is  the  visual  purple  ? 

A  certain  purple  substance  on  the  retina,  which  is  destroyed  by 
contact  with  light.  It  has  been  supposed  that  it  aids  vision,  but 
this  is  apparently  contradicted  by  the  fact  that  it  is  absent  from 
the  cones  and  the  macula  lutea,  where  vision  is  best.  It  can  only 
be  seen  by  opening  an  eye  in  a  dark  room,  and  flashing  a  light 
upon  it.  If  the  operation  be  quickly  done  the  image  falling  on 
the  retinal  pigment  may  be  made  permanent  by  dipping  it  quickly 
in  a  strong  solution  of  alum. 

Does  every  part  of  the  retina  receive  all  the  rays  of  light  ? 
No.     Each  portion  receives  different  colored  rays.     The  periph- 
eral portion  sees  the  red  rays,  etc. 

What  is  the  function  of  the  aqueous  humor  of  the  eye  ? 

It  affords  a  medium  in  which  the  iris  can  move.  It  also  supports 
the  posterior  surface  of  the  cornea,  and  influences  the  refraction  of 
light. 

What  is  the  function  of  the  vitreous  humor  ? 

It  fills  out  the  eyeball  and  keeps  it  tense,  and  aids  very  largely 
in  the  refraction  of  the  rays  of  light  transmitted  to  it  through  the 
crystalline  lens. 

What  is  the  function  of  the  crystalline  lens  ? 

It  acts  like  a  strong,  magnifying  glass,  and  is  biconvex.  It  is 
the  most  important  refracting  portion  of  the  eye,  and,  aided  by 
other  portions  of  the  optical  apparatus,  directs  the  rays  of  light  in 
such  a  manner  that  they  fall  properly  on  the  retina.  It  also  sepa- 
rates the  aqueous  from  the  vitreous  humor. 

In  what  way  are  images  thrown  on  the  retina  ? 
They  are  inverted  by  the  lens,  which  is  biconvex. 

Why  do  we  not  see  objects,  therefore,  upside  down? 

Because  the  brain  interprets  the  inverted  image  for  one  in  the 
proper  position. 


THE    SENSE    OF    SIGHT.  155 

What  variation  is  there  in  the  power  of  refraction  of  the 
various  parts  of  the  lens  ? 
It  increases  in  density,  and  consequently  in  power  of  refraction, 
from  without  inward. 

Give  the  essential  portions  of  the  eye  for  the  carrying  out 
of  its  functions,  namely,  sight. 

1.  A  retina  or  nervous  mass  to  receive  and  transmit  impulses. 

2.  Certain  refracting  media  so  arranged  as  to  throw  the  rays  of 
light  in  proper  form. 

.'!.  A  contractile  diaphragm,  the  iris,  which  governs  quantity  of 
light  admitted. 

4.  A  contractile  muscle,  the  ciliary  muscle,  to  regulate  the  shape 
of  the  lens  and  to  "  accommodate"  the  eye  to  distances. 

What  would  be  the  effect  if  the  retina  was  exposed  to  the 
light  with  no  refracting  media  in  front  of  it  ? 
The  perception  of  light  from  darkness,  but  no  objects  could  be 
seen. 

What  do  you  mean  by  the  terms  "refraction  and  accom- 
modation of  the  eye  ?  " 
By  refract io/t  we  understand  that  optical  adjustment  of  the  eye 
which  depends  upon  its  anatomical  structure;  the  accommodation 
includes  those  changes  of  the  optical  adjustment  which  are  effected 
by  the  ciliary  muscle. 

When  the  eye  is  at  rest  is  it  accommodated  to  near  or  far 
objects? 
It  is  accommodated  for  the  greatest  distance. 

What  do  you  mean  by  the  "  near  point?  " 

The  "near  point"  is  the  nearest  point  at  which  the  eye  can 
clearly  perceive  an  object  held  before  it,  as,  for  example,  printed 
matter  held  close  to  the  face. 

The  "far  point"  is  the  same  thing  reversed,  save  that  the  far 
point  in  the  human  eye  is  an  infinite  distance. 

By  what  means  do  we  judge  of  distance  ? 
This  is  largely  a  matter  of  education  and  is  unconsciously  ob- 


156        ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

tained,  in  the  same  way  as  the  judgment  of  size,  a  mere  matter  of 
practice. 

What  is  chromatic  aberration  ? 

It  is  the  breaking  up  of  ordinary  white  light  into  colored  rays, 
owing  to  the  different  colored  lights  of  which  ordinary  light  is 
made  up.  It  is  due  to  a  defect  in  the  optical  apparatus,  but  in  the 
normal  eye  it  is  diminished  by  the  iris,  which  cuts  off  the  marginal 
rays. 

What  is  spherical  aberration  ? 

It  depends  upon  the  fact  that  luminous  rays  passing  through  a 
convex  lens  strike  the  various  parts  of  the  surface  at  different 
angles,  and,  hence,  are  differently  refracted,  the  rays  striking  the 
margin  of  the  lens  being  more  bent  than  those  passing  through 
the  centre.  Spherical  aberration  does  not,  however,  cause  in- 
convenience, since  the  iris  allows  only  the  central  rays  to  pass. 

What  is  astigmatism  ? 

It  consists  in  an  inability  to  see  clearly  lines  running  at  certain 
angles. 

It  depends  either  upon  some  irregularity  in  the  shape  of  the 
cornea,  or  in  the  shape  of  the  lens. 

What  are  entopic  images? 

Those  which  depend  on  the  presence  of  some  opacity  in  the 
transparent  media  of  the  eye  itself.  They  occur  in  all  eyes  to  a 
a  certain  extent,  and  are  frequently  noticed  when  one  uses  the 
microscope. 

What  is  the  cause  of  color-blindness  ? 

The  inability  of  certain  areas  of  the  retina  to  perceive  those 
rays  of  light  which  normally  fall  on  them,  owing  to  the  imperfect 
development  of  these  areas.  The  common  forms  of  blindness  are 
for  the  red,  green,  and  yellow  rays. 

What  is  diplopia  ? 

Double  vision,  due  to  the  fact  that  each  eye  receives  the  impulse 
at  a  different  time  from  the  other. 


THE    SENSE    OF    SIGHT.  157 

What  is  hemianopsia  ? 

Blindness  of  one-half  of  the  eye  so  that  objects  are  split  down 
the  middle  and  only  half  of  the  body  perceived.  Since  the  rays 
of  light  cross  in  the  eye,  the  part  of  the  retina  which  is  blind  is 
always  opposite  the  object,  which  cannot  be  seen.  Thus,  when  the 
eye  sees  no  objects  to  the  left  of  it,  it  is  the  right  side  of  the  eye 
which  is  blind. 

What  is  myopia? 

"Short  sightedness."  A  condition  of  the  eye  in  which  objects 
are  focussed  at  a  point  in  front  of  the  retina. 

What  is  hypermetropia? 

"  Far  sightedness."  A  condition  of  the  eye  in  which  objects  are 
focussed  behind  the  retina. 

What  do  you  mean  by  presbyopia  ? 

A  state  common  to  old  age,  due  to  loss  of  the  power  of  accom- 
modation. 

What  is  an  emmetropic  eye  ? 
A  normal  eye. 

Does  such  an  eye  as  an  absolutely  normal  eye  exist  ? 
Probably  not,  or  in  very  rare  instances. 

By  what  form  of  glass  would  you  remedy  myopia  ? 
By  a  concave  glass. 

By  what  form  of  glass  would  you  relieve  hypermetropia  ? 
By  a  convex  glass. 

Why  do  you  do  this  ? 

Because  in  the  myopic  eye  the  lens  is  too  convex,  while  in  the 
hypermetropic  eye  it  is  not  convex  enough.  While  this  is  often 
the  case,  the  fault  generally  depends  on  a  misshapen  eyeball. 


158         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  do  you  mean  by  dioptric  media  ? 

Transparent  bodies  wbicb  so  refract  tbe  light  that  images  come 
to  a  focus  on  the  retina. 

What  do  you  mean  by  intraocular  pressure? 

The  tension  to  which  the  coats  of  the  eyeball  are  put  by  the 
varying  quantity  of  the  humors  of  the  eye.  When  the  tension  is 
increased  abnormally  it  is  called  glaucoma. 

What  do  you  mean  by  the  Argyll  Robinson  pupil  ? 

An  abnormal  condition  of  the  pupil  in  which  it  does  not  con- 
tract to  light,  but  does  contract  when  accommodation  is  carried  on. 

What  is  nystagmus  ? 

Gowers  think  that  it  is  due  to  faulty  fixation  of  the  eyeball  by 
the  reflexes  which  generally  keep  it  steady.  Either  the  stimula- 
tion of  the  reflexes  is  insufficient  or  too  great.  In  albinoes  we  often 
have  it  because  of  too  much  stimulation  from  light.  In  children 
blind  soon  after  birth  it  also  comes  on  before  the  steadying  centres 
can  be  developed. 


Hearing. 

In  the  same  way  that  all  impulses  travelling  along  the  optic 
nerve  are  interpreted  as  light,  so  are  all  the  impulses  travelling 
along  the  auditory  nerve  interpreted  as  sound. 

Through  how  many  divisions  of  the  ear  does  the  sound 

7 


Three  ;  the  external  ear  and  auditory  canal,  the  middle  ear, 
which  is  shut  off  from  the  auditory  canal  by  the  tympanic  mem- 
brane, and  the  labyrinth . 


HEARING.  159 

What  is  the  purpose  of  the  external  ear  ? 
To  collect  sound. 

What  is  the  function  of  the  auditory  canal  ? 
By  circumscribing  the  air  it  increases  its  vibrations. 

What   is  the   function   of  the    cerumen  of  the   external 
ear1? 
To  catch  foreign  bodies  which  might  otherwise  enter. 

What  is  the  function  of  the  tympanic  membrane  ? 

It  receives  the  vibrations  of  the  air  in  the  auditory  canal,  trans- 
mitting them  to  the  bones  of  the  middle  ear. 

For  what   purpose  is  the  tympanic  membrane  sloped  from 
outward  inward? 

By  this  means  it  more  readily  responds  to  sounds  of  varying 
character  and  can  be  of  greater  dimensions. 

By  what  means  are  the  vibrations  of  sound  transmitted 
after  leaving  the  tympanic  membrane  ? 

Three  small  bones  known  as  the  malleus,  incus,  and  stapes  join 
together,  and  reach  from  the  membrane  to  a  secondary  membrane 
which  covers  the  oval  window  leading  into  the  vestibule  of  the 
internal  ear;  the  malleus  is  attached  to  the  tympanic  membrane, 
while  the  stapes  is  in  contact  with  the  oval  window. 

What  is  the  function  of  the  stapedius  muscle  ? 

It  is  attached  to  the  stapes,  and  when  it  contracts  pulls  that 
bone  away  from  the  oval  window,  otherwise  a  loud  sound  might 
jam  the  bone  into  the  oval  window  and  produce  deafness. 


160       ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  is  the  function  of  the  tensor  tympani  muscle? 

By  drawing  the  handle  of  the  malleus  internally  it  increases 
the  tenseness  of  the  tympanic  membrane  and  prevents  it  from 
vibrating  too  much  to  sounds  of  great  intensity. 

What  is  the  function  of  the  laxator  tympani  muscle  ? 

It  draws  the  handle  of  the  malleus  outward,  and  relaxes  the 
tympanic  membrane. 

What  is  the  function  of  the  Eustachian  tube  ? 

It  communicates  with  the  pharynx  and  opens  into  the  middle 
ear  back  of  the  tympanic  membrane,  affording  vent  by  which, 
when  the  drum  is  driven  in,  some  of  the  air  may  escape.  It 
equalizes  the  pressure  within  and  without. 

Is  the  Eustachian  tube  constantly  open? 

No,  it  is  not ;  if  it  were,  the  various  sounds  in  the  mouth  would 
produce  sounds  in  the  ear. 

In  what  way  is  sound  transmitted,  after  passing-  through 
the  ossicles,  to  the  terminal  filaments  of  the  audi- 
tory nerve  ? 
Through  the  semicircular  canals  and  the  spiral  staircase. 

What  fills  the  semicircular  canals? 

A  liquid  known  as  the  endolymph. 

In  what  manner  does  the  endolymph  receive  impulses  from 
the  exterior  ? 

The  endolymph  is  in  direct  contact  with  the  membrane  which 
covers  the  oval  window,  and  when  the  stapes  strikes  against  this 
membrane  it  produces  vibrations  which  are  taken  up  by  the  endo- 
lymph. 

In  what  way  do  the  nerves  end  in  the  semicircular  canals  ? 
In  peculiar  epithelioid  cells,  to  which  are  attached  fine  hair- like 
processes. 

What  are  the  functions  of  the  otoliths  ? 
These  small  calcareous  masses  are  set  in  motion  by  the  vibra- 


THE    VOICE    AND    SPEECH.  161 

tions  of  the  endolymph  and  come  in  contact  with  the  endings  of 
the  nerves,  producing  impulses.  The  function  of  those  nerve  fibres 
which  run  to  the  cochlea  is  not  clearly  understood. 

What  function  have  the  semicircular  canals  other  than 
hearing  ? 
They  appear  to  govern  equilibrium,  for  if  injured  the  animal 
immediately  loses  its  balance.  When  the  horizontal  canal  is 
divided  the  animal  rolls  its  head  from  side  to  side.  When  one  of 
the  vertical  cauals  is  cut  the  head  moves  up  and  down. 

Does  section  of  the  semicircular  canals  destroy  the  power 
of  hearing? 
No;  it  influences  it  very  slightly. 

What  is  the  function  of  the  organ  of  Corti? 

It  is  not  distinctly  known,  but  it  was  supposed  to  be  especially 
developed  in  persons  with  musical  tendencies,  till  it  was  found 
that  the  pig  possessed  them  in  a  highly  developed  state.  As 
nerve  filaments  end  in  these  rods,  it  has  been  supposed  that  each 
set  of  rods  responds  to  a  certain  set  of  notes. 

What  differences  in  sound  can  the  ear  distinguish  ? 

Loudness,  pitch,  and  quality.  The  judging  of  the  distance  from 
which  a  sound  is  transmitted  is  purely  a  matter  of  training. 

The  Voice  and  Speech. 

With  scarcely  any  exception  all  air-breathing  vertebrates  possess 
some  arrangement  for  the  production  of  sound  in  some  part  of 
the  respiratory  apparatus.  In  some  animals  various  modifications 
of  this  sound  are  produced.  In  man  its  modifications  are  so  great 
as  to  permit  of  speech. 

In  what  way  is  the  voice  or  sound  produced? 

By  an  expiratory  blast  of  air  being  forced  through  the  narrow 
opening  at  the  top  of  the  windpipe,  called  the  glottis.  The  glottis. 
it  will  be  remembered,  lies  in  the  lower  part  of  the  larynx  and  is 
bounded  on  each  side  by  thin  membranous  bands,  which,  extend- 
ing from  side  to  side,  vibrate  as  the  air  rushes  over  them.  For 
this  reason,  opening  of  the  trachea  prevents  speech,  since  all  the 
air  rushes  out  of  the  opening  rather  than  over  the  cords. 


162      ESSENTIALS    OF     HUMAN     PHYSIOLOGY. 

What  are  the  chief  organs  of  the  voice? 

The  vocal  cords.  These  are  governed  by  the  muscles  of  the 
larynx.1 

What  is  the  function  of  the  larynx  ? 

It  acts  as  a  cavity  in  which  the  vocal  cords  may  produce  the 
voice. 

What  is  the  function  of  the  thyroid  and  cricoid  cartilages? 

The  function  of  these  two  cartilages  is  chiefly  for  the  purpose  of 
affording  stiff  walls  around  the  vocal  apparatus  for  the  sake  of 
protection  and  attachment.  The  thyroid  cartilage  forms  an  in- 
complete ring  around  the  larynx,  and  covers  only  the  front  portion 
and  sides.  The  cricoid  cartilage,  on  the  other  hand,  is  a  complete 
ring,  the  back  part  of  the  ring  being  broader  than  the  front. 

What  is  the  function  of  the  arytenoid  cartilages  ? 

They  are  situated  on  the  top  of  the  back  portion  of  the  cricoid 
cartilage  and  are  movable  upon  it,  forming  a  place  for  the  inser- 
tion of  certain  muscles  concerned  in  speech. 

What  are  the  intrinsic  muscles  of  the  larynx  ? 

They  are  those  which  have  a  direct  action  on  the  vocal  cord, 
and  are  nine  in  number — four  pairs  and  a  single  muscle:  two 
crico-thyroids,  two  thyro-arytenoids,  two  posterior  crico-arytenoids, 
two  lateral  crico-arytenoids,  and  one  arytenoid  muscle. 

What  are  the  functions  of  these  muscles  ? 

When  the  crico-thyroids  contract  they  rotate  the  cricoid  on  the 
thyroid  cartilage  in  such  a  manner  that  the  upper  and  back  part 
of  the  former,  and  of  necessity  the  arytenoid  cartilages  on  the  top 
of  the  cricoid  cartilage,  are  tipped  backward,  while  the  thyroid  is 
inclined  forward.  The  result  of  this  is  that  the  vocal  cords  being 
attached  in  front  to  the  thyroid  cartilage  and  posteriorly  to  the 
cricoid  cartilage  are  put  on  the  stretch.  The  thyro-arytenoid 
muscles  have  an  opposite  action,  for  they  pull  the  thyroid  back- 
ward and  the  arytenoid  and  the  upper  and  back  part  of  the  cricoid 

1  For  the  anatomy  of  the  larynx  and  those  portions  of  the  body  concerned  in  speech, 
see  an  anatomical  text-book. 


THE    VOICE    AND    SPEECH.  163 

cartilages  forward,  thus  relaxing  the  vocal  cords.  The  posterior 
crico-arytenoids  dilate  the  glottis  and  separate  the  vocal  cords  by 
an  action  on  the  arytenoid  cartilage.     When  they  contract  they 

pull  together  the  outer  angles  of  the  arytenoid  cartilages  in  such 
a  manner  as  to  rotate  the  latter  at  their  joint  with  the  cricoid,  and 
to  throw  asunder  their  anterior  angles  to  which  the  vocal  cords 
are  attached. 

What  muscles  oppose  these  posterior  crico-arytenoid 
muscles? 
The  lateral  crico-arytenoids,  which,  pulling  in  the  opposite 
direction  from  the  other  side  of  the  axis  of  rotation,  have,  of 
course,  exactly  the  opposite  effect,  and  enclose  the  glottis.  The 
arytenoid  muscle  may  also  close  the  glottis  almost  completely,  by 
pulling  together  the  upper  parts  of  the  arytenoid  cartilages, 
between  which  it  extends. 

What  is  the  nervous  mechanism  of  the  voice  ? 

The  sensory  filaments  in  the  pneumogastric  give  the  glottis  that 
acute  sensibility  which  prevents  the  ingress  of  foreign  bodies  or 
noxious  gases  into  the  air-passages.  The  superior  laryngeal 
branch  of  the  vagus  and  the  inferior  laryngeal  branch,  or  the  re- 
current nerve,  cooperate  not  only  with  the  pneumogastric  in  the 
closure  of  the  glottis  which  excludes  foreign  bodies,  but  also  in 
the  protection  and  regulation  of  the  voice.  The  inferior  laryn- 
geal nerve  governs  the  contraction  of  the  muscles  that  vary  the 
tension  of  the  vocal  cords,  while  the  superior  laryngeal  convey-  {•< 
the  mind  the  sensations  of  the  state  of  these  muscles,  which  is 
absolutely  necessary  for  their  intelligent  guidance. 

What  three  properties  are  possessed  by  the  human  voice? 
Quality,  pitch,  and  intensity. 

Over  how  wide  a  musical  range   does  the    human  voice 
extend  ? 

Including  all  4bnns  of  voice,  about  three  and  one-half  octaves; 
but  of  this  wide  range  a  single  individual  can  rarely  sing  more 
than  two  octaves. 


164         ESSENTIALS    OF    HUMAN    PHYSIOLOGY 

What  difference  exists  between  the  notes  of  the  female 
voice  and  those  of  the  male  ? 
The  lowest  note  of  the  female  voice  is  about  an  octave  higher 
than  the  lowest  note  of  the  male  voice.  The  highest  note  of  the 
female  voice  is  about  an  octave  higher  than  the  highest  note  of 
the  male. 

In  what  portion  of  the  vocal  apparatus  is  the  variation  in 
sound  produced  which  results  in  speech  ? 
Not  in  the  larynx,  but  in  the  mouth  and  nose,  by  means  of  the 
teeth,  tongue,  and  lips. 

What  sound  do  we  have  when  speech  is  not  accompanied 
by  the  action  of  the  vocal  cords  ? 
Only  a  whisper. 

What  effect  upon  sound  has  approximation  of  the  vocal 
cords  ? 

The  sound  emitted  is  high  pitched  in  character,  while  non- 
approximation  of  the  cords  produces  sound  of  greater  volume,  but 
of  lower  pitch.  The  pitch  does  not  depend,  however,  absolutely 
on  the  approximation  or  non-approximation  of  the  cords,  but 
more  upon  the  tensity  of  the  cords  themselves. 

What  is  the  function  of  the  epiglottis  in  regard  to  sound  ? 
When  pressed  down  so  as  to  cover  the  cavity  of  the  larynx  it 
serves  to  render  the  notes  deeper  in  tone,  and,  at  the  same  time, 
somewhat  fuller  in  quality. 

What  is  aphasia  ? 

The  partial  or  complete  loss  of  the  power  of  articulate  speech 
from  causes  arising  in  the  cerebrum. 

What  is  the  difference  between  aphasia  and  aphonia  ? 

Aphasia  is  the  derangement  of  the  mental  functions  immediately 
connected  with  word-thought,  while  aphonia  is  the  term  applied 
to  the  voicelessness  of  laryngeal  disease. 


THE    SYMPATHETIC    NERVE.  165 

What  is  the  term  aphaemia  applied  to? 

It  is  usually  used  to  signify  a  condition  of  speechlessness  due  to 
inability  to  execute  the  normal  movements  of  the  mouth  and 
tongue.     This  condition  is  sometimes  called  ataxic  aphasia. 

Does  a  patient  who  is  aphasic  still  have  the  power  to 
think,  and  does  he  still  remember  words  ? 
Yes;  and  he,  therefore,  can  express  himself  in  writing. 

What  do  you  mean  by  the  term  amnesic  aphasia? 

It  is  the  condition  in  which  the  idea  is  present  but  the  word  is 
wanting,  although  articulation  is  ''  at  the  service  of  the  word." 
The  movements  in  this  condition  are  correct,  so  far  as  speech  is 
concerned,  but  the  patient  cannot  think  of  the  word  to  speak  it. 
This  condition  is  often  seen  in  old  persons  to  a  slight  extent,  and 
is  called  amnesia  senilis. 

What  is  paraphasia  ? 

The  inability  to  connect  rightly  ideas  with  the  proper  words  to 
express  them,  so  that  instead  of  giving  expression  to  the  ideas 
the  sense  may  be  inverted. 

What  is  agrammatism  ? 

The  inability  to  form  the  words  grammatically  and  arrange 
them  in  sentences. 

What  is  bradyphasia  ? 
A  pathological  slowness  of  speech. 

The  Sympathetic  Nerve. 

It  will  be  remembered  that  the  sympathetic  system  contains  a 
very  large  number  of  non-medullated  nerve  fibres,  and  consists  of 
a  double  gangliated  prevertebral  cord,  one  on  each  side  of  the 
vertebral  column. 

What  are  the  rami  communicantes  ? 

The  nerves  given  off"  by  the  spinal  nerves  to  the  sympathetic 
cord.     Each  spinal  nerve  does  this. 


166         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  do  you  mean  by  the  cephalic,  dorsal,  and  abdominal 
portions  of  the  sympathetic? 
Those  portions  which  govern  these  areas.      In  the  head  the 
cephalic  portion  anastomoses  with  the  cranial  nerves  to  a  great 
extent.     The  abdominal  portion  supplies  the  abdominal  organs. 

What  are  the  functions  of  the  sympathetic? 

First,  the  independent  functions  as  represented  by  the  automatic 
cardiac  ganglia,  the  mesenteric  plexus  of  the  intestine,  and  the 
plexuses  of  the  uterus,  Fallopian  tubes,  ureters,  and  lymph  and 
bloodvessels.  They  are  independent  in  that  they  are  capable  of 
acting  without  any  impulses  from  higher  centres,  but  they  may 
also  be  governed  by  the  spinal  centres  under  some  circumstances. 
Second,  the  dependent  functions  which  are  governed  by  centres,  as, 
for  example,  the  sensory  fibres  of  the  splanchnics. 

What  is  the  function  of  the  cervical  sympathetic  ? 

It  contains  (1)  pupil-dilating  fibres  which,  according  to  Budge, 
arise  from  the  spinal  cord  and  run  through  the  upper  two  dorsal 
and  lowest  cervical  nerves  into  the  cervical  sympathetic,  which 
conveys  them  to  the  head. 

What  does  the  cervical  sympathetic  also  supply  ? 

(2)  Motor  fibres  for  Miiller's  smooth  muscle  of  the  orbit,  and 
partly  for  the  external  rectus  muscle  of  the  eye.  It  also  supplies 
(3)  vaso-motor  branches  for  the  outer  ear  and  the  side  of  the  face, 
tympanum,  iris,  choroid,  retina  in  part,  the  oesophagus,  larynx, 
thyroid  gland,  and  fibres  for  the  vessels  of  the  brain  and  its  mem- 
branes ;  (4)  secretory  and  vaso-motor  fibres  for  the  salivary  glands. 
(5)  Sweat  secretory  fibres  are  given  off,  as  are  also  secretory  fibres 
to  the  (6)  lachrymal  glands,  according  to  Wolferz  and  Demtschenko. 

What  are  the  functions  of  the  thoracic  and  abdominal 
sympathetic  ? 
(1)  The  sympathetic  portion  of  the  cardiac  plexus,  which  receives 
accelerating  fibres  for  the  heart  from  the  lower  cervical  and  first 
thoracic  ganglion.  (2)  The  cervical  sympathetic  and  the  splanch- 
nics contain  fibres  which,  when  their  central  ends  are  stimulated, 
excite  the  cardio-inhibitory  centre  in  the  medulla. 


GENERATION    AND    DEVELOPMENT.  167 

Give  an  example  of  this. 

[f  an  animal  be  struck  sharply  on  the  belly,  over  tbe  Bolar 
plexus,  death  may  result  from  cardiac  stoppage  due  to  reflex 
inhibition. 

What  is  the  splanchnic  ? 

The  splanchnic  is  a  division  of  the  sympathetic,  and  contains 
vaso-motor  filaments.  All  the  vaso-motor  nerves  do  not  run 
through  the  cord,  but  some  of  them  leave  the  cord  high  up  and 
pass  into  the  sympathetic.  These  nerve  filaments  in  the  splanch- 
nics  govern  the  bloodvessels  of  the  abdomen  very  largely.  The 
splanchnic  also  contains  vaso-motor  fibres  which  supply  the 
kidneys. 

What  effect  has  section  of  the  cervical  sympathetic,  or  its 
rami  communicantes,  on  the  pupil? 
It  causes  contraction  of  the  pupil. 

What  other  effect  has  section  of  the  cervical  sympathetic  ? 

It  causes  increased  fulness  of  the  bloodvessels  on  that  side,  the 
eyelids  are  not  held  well  apart,  while  the  eyeball  is  sunken  and 
retracted.  Sometimes  unilateral  atrophy  of  the  face  comes  on.  If 
this  section  be  performed  in  young  growing  animals,  hypertrophy 
of  that  ear  and  side  of  face  occurs,  owing  to  the  increased  blood 
supply  and  other  trophic  changes. 

What  is  the  effect  of  stimulation  of  the  cervical  sympa- 
thetic ? 
It  causes  dilatation  of  the  pupil,  and  occasionally  hyperidrosis 
or  profuse  sweating  of  that  side  of  the  head.  There  is  also  pro- 
trusion of  the  eyeball,  and  the  eyelids  are  held  wide  open.  The 
eyeball,  instead  of  being  sunken,  as  after  section,  is  in  a  condition 
of  exophthalmos. 

GENERATION  AND  DEVELOPMENT. 

What  do  you  mean  by  generation  and  development  ? 

The  first  term  signifies  the  original  cause  of  growth,  while  the 
second  term  signifies  the  manner  of  growth  after  it  is  once  begun. 


168        ESSENTIALS    OP    HUMAN    PHYSIOLOGY, 

Generative  Organs  of  the  Female. 

They  consist  of  two  ovaries,  two  Fallopian  tubes  or  oviducts,  Vhe 
uterus,  and  a  canal  known  as  the  vagina. 

What  is  the  function  of  the  ovaries  ? 
The  formation  of  the  ova  or  eggs. 

What  is  the  function  of  the  Fallopian  tubes  or  oviducts  ? 

The  conduction  of  the  ova  from  the  ovaries  to  the  uterus. 

What  is  ^he  function  of  the  uterus  ? 

It  is  a  cavity  in  which,  if  impregnated,  the  ovum  is  retained 
until  it  is  fully  developed  and  capable  of  maintaining  its  life  inde- 
pendent of  the  parent. 

What  is  the  function  of  the  vagina? 

It  is  the  canal  which  receives  the  male  generative  organ,  the 
penis,  in  the  act  of  copulation,  and  is  the  passage  through  which 
the  foetus  is  discharged. 

Describe  the  ovaries. 

They  are  two  oval  bodies  situated  in  the  cavity  of  the  pelvis,  one 
on  each  side,  inclosed  in  the  folds  of  the  broad  ligaments.  Each 
ovary  measures  about  an  inch  and  a  half  in  length  and  three- 
quarters  of  an  inch  in  width.  They  are  about  half  an  inch  in 
thickness,  and  are  attached  to  the  uterus  by  a  narrow  fibrous  cord, 
the  ligament  of  the  ovary,  and  more  slightly  to  one  of  the  fimbria? 
of  the  Fallopian  tubes.  They  are  enveloped  by  a  dense  fibrous 
tissue.  They  are  covered  on  the  exterior  by  the  germ  epithelium. 
The  inner  substance,  or  stroma,  is  a  soft  fibrous  tissue  containing, 
imbedded  in  it,  a  number  of  vesicles  in  various  stages  of  develop- 
ment. 

What  are  these  vesicles  called  ? 
Graafian  vesicles. 


GENERATION    AND    DEVELOPMENT.  169 

In  what  way  do  the  Fallopian  tubes  grasp  the  ovule  when 
it  is  expelled  from  the  ovary? 
By  means  of  their  fimbriated  extremities,  which  are  in  constant 
ciliary  movement. 

Describe  the  formation  of  the  ovule  in  the  ovary. 

The  vesicles  in  the  stroma  gradually  approach  the  surface  until 
they  project  above  it.  Each  follicle  or  vesicle  is  covered  by  an 
external  membranous  envelope  lined  with  a  layer  of  nucleated 
cells,  the  membrana  granulosa.  This  follicle  contains  liquid  full  of 
small  microscopic  bodies,  with  the  ovule  nearly  in  its  centre,  unless 
the  follicle  is  fully  matured  when  it  comes  in  contact  with  the 
membrana  granulosa. 

What  is  the  discus  proligerus  ? 

A  granular  zone  of  the  nucleated  cells  of  the  membrana  granu- 
losa,  which  is  heaped  around  about  the  ovule. 

What  is  the  size  of  the  human  ovule? 
About  T^jjth  of  an  inch. 

What  is  the  zona  pellucida  or  vitelline  membrane  ? 

The  investment  of  the  ovule,  and  it  adheres  closely  to  the  discus 
proligerus. 

What  lies  within  the  zona  pellucida  ? 

The  yelk  or  vitellus,  which  is  composed  of  granules  and  globules 
of  various  sizes. 

What  arrangement  have  these  globules  ? 
The  largest  are  at  the  periphery,  the  smallest  are  at  the  centre. 

What  does  the  yelk  or  vitellus  contain? 
The  germinal  vesicle  or  the  vesicula  germinativa. 

What  does  this  germinal  vesicle  contain? 

At  its  periphery,  at  the  point  nearest  the  yelk,  it  contains  the 
germinal  spot  or  the  macula  germinativa. 

These  are  all  the  parts  of  the  Graafian  follicle. 


170         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

Does  the  formation  of  Graafian  follicles  go  on  constantly 
during-  the  child-bearing  part  of  life  ? 

Yes. 

What  do  you  mean  by  the  discharge  of  the  ovule  ? 

When  the  follicle  is  ripe  and  has  reached  the  surface  of  the 
ovary,  the  follicular  wall  becomes  thinner  and  finally  bursts.  The 
ovule  and  its  fluid  surroundings  escape  on  the  surface  of  the  ovary, 
which  is  grasped  by  the  Fallopian  tube,  down  which  the  ovule 
travels. 

Is  there  any  difference  in  the  periodicity  of  the  maturity  of 
the  ovule  in  the  different  varieties  of  animals  ? 
Yes;  in  human  beings  it  is  once  in  every  twenty-eight  days, 
while  in  the  common  fowl  it  is  constant. 

What  is  the  difference  between  the  ovule  and  the  ovum  ? 

The  term  ovule  is  ordinarily  applied  to  the  egg  previous  to 
impregnation,  while  the  ovum  is  the  fecundated  ovule. 

What  is  menstruation  ? 

It  is  regarded  by  most  physiologists  as  the  flow  of  blood  accom- 
panying the  discharge  of  a  ripened  ovule.  The  rupture  of  a 
follicle  is  not  necessarily  accompanied  by  menstruation,  neither  is 
menstruation  necessarily  followed  by  ovulation. 

Does  rupture  of  the  follicle  take  place  before  or  after  the 
flow? 

In  most  cases  before  or  at  the  beginning ;  more  rarely  at  the 
middle  or  end  of  menstruation. 

Describe  the  menstrual  discharge. 

It  is  a  thin,  sanguinolent  fluid  having  a  peculiar  odor,  and 
consists  of  blood,  epithelium,  the  mucus  of  the  uterus  and  vagina, 
and  the  remains  of  the  mucous  membrane  lining  the  uterus. 

What  is  this  mucous  membrane  called? 

The  decidua  menstruaMs,  which  is  developed  to  perfection  just 
before  the  menstrual  flow  and  then  thrown  off. 


GENERATION    AND    DEVELOPMENT.  171 

Can  menstruation  be  regarded  as  a  hemorrhage  ? 

No;  it  can  not.  It  is  merely  a  destructive  process  whereby  the 
membrane  which  was  prepared  for  receiving  a  fecundated  ovule  is 
thrown  off. 

At  what  time  of  life  does  menstruation  begin  and  end  in 
the  temperate  zone  ? 
It  begins  at  twelve  or  fourteen  years  of  age,  and  ceases  at  a  peril  id 
between  forty  and  fifty. 

Does   menstruation   ever    occur   during  pregnancy,  or  in 
nursing  women? 
Rarely ;  but  such  cases  are  on  record. 

What  is  the  corpus  luteum  ? 

At  the  time  of  rupture  of  the  Graafian  vesicle,  a  yellowish  mass, 
the  corpus  luteum,  develops  itself.  It  is  a  round,  solid  body  whose 
walls,  after  the  rupture,  become  covered  by  small  buds  of  Hesh- 
like  matter,  resembling  a  granulating  wound,  and  these  granula- 
tions extend  above  the  ovarian  surface.  Ultimately  they  become 
covered,  but  still  go  on  growing  inside  the  ovary.  As  pregnancy 
goes  on,  the  red  granulations  change  to  yellow  and  its  consistence 
becomes  firmer. 

Does  the  corpus  luteum  depend  for  its  formation  on  the 
effusion   of    blood   which   takes    place    when   the 
follicle  ruptures  ? 
Not  in  the  least.      Remember   this.     The  corpus   luteum  is,  in 

reality,  a  growth  of  cells  from  the  membrana  granulosa. 

What  difference  is  there   in  the   growth   of   the   corpus 
luteum  of  pregnancy  and  in  that  of  ordinary  men- 
struation? 
In  pregnancy  it  remains  till  gestation  is  nearly  ended.     When 

impregnation  does  not  occur  it  shortly  disappears. 

The  Male  Sexual  Organs. 

What  is  the  function  of  the  testicles? 
They  are  the  organs  which  secrete  portions  of  the  semen. 


172        ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

What  other  tissues  aid  in  this  secretion? 

The  vesiculae  seminales,  the  prostate  gland,  and  Cowper's  glands. 

What  does  the  semen  consist  of? 

Of  the  secretion  of  all  these  tissues. 

In   what   way  is   the    secreting-   portion   of  the   testicle 
arranged? 

Into  two  parts,  one  of  which  is  the  body  of  the  testicle  inclosed 
within  a  tough,  fibrous  membrane,  the  tunica  albuginea,  which  is 
covered  externally  by  a  serous  membrane,  the  tunica  vaginalis. 
The  second  part  is  the  epididymis  and  vas  deferens. 

What  is  the  vas  deferens,  and  what  is  its  function  ? 

It  is  the  duct  of  the  testicle,  about  two  feet  in  length.  It  passes 
to  the  lower  part  of  the  epididymis,  with  which  it  is  continuous, 
where  it  becomes  exceedingly  tortuous  in  its  course. 

Of  what  does  the  epididymis  consist? 

Of  a  single  tube  about  twenty  feet  long. 

What  are  the  tubuli  seminiferi  ? 
They  make  up  the  parenchyma  of  the  organ. 

In  what  way,  and  from  what  are  the  spermatozoids  formed? 

The  seminal  tubule  is  limited  by  an  elastic  membrane,  the  mem- 
brana  propria,  inside  of  which  are  several  layers  of  cells,  known  as 
the  seminal  cells. 

How  many  kinds  of  seminal  cells  have  we  ? 

Two.  Those  resting  quietly,  others  in  a  state  of  active  division. 
The  active  cells  are  called  the  mother  cells ;  and  the  smaller  cells, 
resulting  from  their  division,  the  daughter  cells  or  spermatoblasts. 
The  spermatozoids  are  formed  from  the  spermatoblasts. 

What  is  the  appearance  of  the  spermatozoid? 

It  consists  of  a  small  body  or  head,  to  which  is  attached  a  cilium, 
or  rapidly  moving  tail. 


GENERATION    AND    DEVELOPMENT.  173 

What  is  the  function  of  the  spermatozoids  ? 

They  are  absolutely  needful  for  impregnation,  and  it  is  the  sper- 
matozoids which  fecundate  the  ovule. 

How  does  the  semen  reach  the  exterior  of  the  body  ? 

It  is  secreted  in  the  tubules  of  the  testicles,  then  passes  along 
the  vasadeferentia  into  the  vesiculseseminales,  and  from  there  into 
the  urethra. 

What  is  the  function  of  the  seminal  vesicles  other  than  the 
carrying  off  of  the  semen? 
They  secrete  some  of  the  liquid  in  which  the  spermatozoids  float 
or  swim.     This  is  probably  their  chief  function,  at  least  in  some 
animals. 

What  is  the  function  of  the  prostate  and  Cowper's  glands? 
To  add  the  proper  liquid  to  the  semen. 

Of  what,  therefore,  does  semen  consist  ? 

The  liquor  seminis  and  the  spermatozoids,  with  detached  epi- 
thelial cells. 

Development. 

In  what  part  of  the  female  genital  organs  does  the  ovule 
become  fecundated? 
Most  commonly  in  the  upper  part  of  the  Fallopian  tube. 

What  changes  take  place  in  the  ovum  or  the  fecundated 
ovule  ? 
The  visible  change  is  a  slight  am<eboid  movement  of  the  proto- 
plasm of  the  ovum,  which  is  shortly  followed  by  segmentation, 
which  consists  in  the  repeated  subdivision  of  the  cells  present. 

How  long  does  this  segmentation  last  ? 

It  is  finished  by  the  time  the  ovum  reaches  the  uterus. 

What  is  seen  in  the  centre  of  each  segment  ? 

A  central  vesicle,  which  is  the  result  of  the  repeated  division  of 
another  central  vesicle,  just  as  the  segments  themselves  are  the 
result  of  the  division  of  the  yelk  itself. 


174         ESSENTIALS    OF    HUMAN"    PHYSIOLOGY. 

What  appearance  has  the  ovum  as  it  enters  the  uterus  ? 

Owing  to  the  many  segmentations,  it  is  granular,  and  resembles 
a  mulberry. 

How  long  a  time  does  the  passage  of  the  ovum  from  the 
ovary  to  the  uterus  take  ? 
Probably  eight  or  ten  days. 

What  is  the  germinal  or  blastodermic  membrane  ? 

It  is  a  membrane  which  is  formed  by  the  accumulation  at  the 
periphery  of  the  yelk  of  a  number  of  the  segments  or  cells.  Owing 
to  their  number  they  are  pressed  against  one  another,  and  become 
polyhedral  in  shape. 

What  are  the  layers  of  the  blastoderm? 

The  epiblast,  mesoblast,  and  hypoblast. 

What  is  the  function  of  the  epiblast  ? 

From  the  epiblast  are  eventually  developed  the  epidermis  and 
its  various  appendages,  the  cerebro-spinal  nerve  centres,  the  sensory 
epithelium  of  the  mouth,  and  the  salivary  glands. 

What  are  developed  from  the  hypoblast  ? 

Theepithelum  of  the  whole  digestive  canal,  and  the  lining  of  all 
the  ducts  which  open  into  it;  the  parenchyma  of  the  liver  and 
pancreas,  and  the  epithelium  of  the  respiratory  tract. 

What  are  developed  from  the  mesoblast  ? 

All  the  organs  not  so  far  mentioned,  all  the  connective  tissues, 
the  muscles,  the  vascular  and  genito-urinary  apparatus,  and  the 
entire  digestive  tract,  save  its  lining  epithelium. 

What  is  the  germinal  area  ? 

The  position  at  which  the  embryo  is  about  to  appear.  It  is  at 
first  circular,  then  pyriform. 

What  is  the  area  pellucida  ? 

A  clear,  transparent  spot,  which  develops  in  the  centre  of  the 
germinal  area. 


GENERATION    AND    DEVELOPMENT.  175 

What  is  the  area  opaca? 

That  portion  of  the  germinal  area  surrounding  the  area  pellucida. 

What  is  the  primitive  groove  ? 

A  shallow  longitudinal  groove  which  is  the  first  trace  of  the 
embryo.     It  appears  near  the  back  part  of  the  area  pellucida. 

What  is  the  medullary  groove  ? 

A  more  permanent  groove  which  soon  replaces  the  primitive 
groove.  It  begins  at  the  anterior  part  of  the  area  pellucida,  ami 
gradually  displaces  the  primitive  groove. 

What  are  the  laminae  dorsales  ? 

Two  longitudinal  elevations  which  bound  the  medullary  canal- 
They  are  folds  of  the  epiblast  which  grow  up  and  extend  over  and 
join  each  other  over  the  medullary  canal,  forming  it  into  a  closed 
canal  or  tube. 

What  is  this  tube  now  called? 
The  primitive  cerebro-spinal  axis. 

At  what  portion  of  the  embryo  do  the  laminae  dorsales 
first  unite  ? 
About  the  neck,  then  the  head,  and  down  to  the   lower  ex- 
tremity. 

What  is  the  notochord  or  chorda  dosalis  ? 

It  is  an  aggregation  of  cells  from  the  mesoblast  immediately 
underneath  or  back  of  the  medullary  canal.  It  extends  nearly  the 
whole  length  of  the  canal,  and  occupies  the  future  position  of  the 
vertebrae. 

What  are  the  protovertebrae  ? 

Square  segments  composed  of  cells  from  the  mesoblast  which 
appear  on  each  side  of  the  medullary  canal  along  its  whole  length. 

What  is  the  "splitting  of  the  mesoblast"? 

Outside  of  the  protovertebrie  the  mesoblastic  cells  are  split  up 
into  two  laminae,  known  as  the  parietal  and  visceral.  These  Laminae 
form  the  origin  for  the  walls  of  the  trunk.  The  parietal  lamina  is 
closely  connected  with  the  epiblast  which  adheres  closely  to  the 


176         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

hypoblast,  and  forms  the  serous  and  muscular  walls  of  the  alimen- 
tary canal  and  other  parts. 

What  is  the  somatopleure  ? 

The  united  parietal  lamina  and  the  epiblast. 

What  is  the  splanchnopleure  ? 

The  united  visceral  layer  and  the  hypoblast. 

What  eventually  becomes  of  the  space  between  the  soma 
topleure  and  the  splanchnopleure? 
It  forms  the  pericardium,  pleurae,  and  peritoneum. 

What  are  the  head  and  tail  folds  ? 

Those  folds  of  the  blastoderm  which  limit  the  embryo  at  the 
head  and  caudal  extremities.  Similar  folds  or  depressions  mark 
off  the  lateral  margins  of  the  embryo,  which  now  finds  itself  entirely 
separate  from  the  yelk  and  surrounded  by  a  clear  space. 

What  is  the  last  portion  of  the  embryo  to  become  com- 
pletely separated  from  the  yelk  ? 
The  head  and  caudal  extremity  are  first  separated,  but  the  an- 
terior wall  of  the  belly  is  not  closed  by  the  folds  till  later.  Indeed 
it  is  never  closed  in  foetal  life,  for  the  umbilicus  is  the  remains  of 
this  connection  with  the  yelk. 

What  is  the  neural  cavity  ? 

That  cavity  formed  by  the  upward  growth  of  the  laminee  dor- 
sales. 

What  is  the  body  cavity  ? 

That  cavity  formed  by  the  downwardly  folded  blastoderm. 

What  are  the  visceral  plates  1 

The  downwardly  folded  portions  of  the  blastoderm  are  known  as 
the  visceral  plates. 

What  forms  the  rudiment  of  the  alimentary  canal  ? 

The  folding  in  of  the  splanchnopleure  lined  by  hypoblast  pinches 
off  a  portion  of  the  yelk-sac  inclosing  it  in  the  body  cavity. 


GENERATION  AND  DEVELOPMENT,     17- 

What  is  the  condition  of  this  rudimentary  alimentary  canal? 
It  is  blind  or  closed  at  both  ends  at  this  time,  while  its  centre 
communicates  freely  with  the  cavity  of  the  yelk-sac. 

What  is  the  canal  called  which  permits  of  this  communi- 
cation ? 
The   vitelline    or   omphalo-mesenteric   duct.      This   condition 
divides  the  yelk-sac  into  two  portions. 

What  is  the  portion  of  the  yelk-sac  outside  the  body  cavity 
called  ? 

The  umbilical  vesicle. 

What  is  the  purpose  of  the  umbilical  vesicle  ? 

It  affurds  nutriment  for  the  embryo. 

In  what  way  does  the  nutriment  reach  the  embryo? 

Through  the  omphalo-mesenteric  vessels  which  ramify  in  the 
walls  of  the  yelk-sac. 

Does  this   yelk-sac  or    umbilical  vesicle   afford  food  all 
through  pregnancy  for  the  embryo  ? 
In  mammalia  it  lasts  only  for  a  short  time,  the  nourishment 
being  derived  from  the  mother. 

What  is  the  amnion  ? 

Beyond  the  head  and  tail  folds  the  somatopleure,  coated  by  epi- 
blast,  rises  in  folds  which  grow  up  and  arch  over  the  embryo, 
anteriorly,  posteriorly,  and  laterally,  all  directed  toward  one  point 
over  the  dorsal  surface  of  the  embryo. 

What  is  the  true  amnion? 

The  inner  of  the  two  layers  of  the  somatopleure  forms  the  true 
amnion. 

What  is  the  false  amnion? 

The  outer  layer  of  the  somatopleure. 

What  is  the  chorion  ? 

It  is  formed  by  the  coalescing  of  the  inner  surface  of  the  original 

vitelline  membrane  with  the  false  amnion. 

12 


1/0         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

How  is  the  amniotic  cavity  formed  ? 

The  cavity  between  the  true  amnion  and  the  external  surface  of 
the  embryo  becomes  a  closed  space,  which  is  called  the  amniotic 
cavity. 

Does  the  amnion  adhere  closely  to  the  embryo  ? 

No,  it  gradually  is  distended  with  fluid  which  separates  it  from 
the  embryo. 

What  is  this  fluid  called,  and  what  is  its  function  ? 

The  liquor  amnii,  which  increases  as  pregnancy  goes  on.  This 
forms  a  yielding  cushion-like  support  for  the  embryo,  protecting 
it  from  injury  and  gradually  distends  the  neck  of  the  uterus  in 
parturition. 

What  is  the  allantois  ? 

It  is  a  highly  vascular  growth,  arising  from  the  hinder  portion 
of  the  peritoneal  cavity,  which  gradually  pushes  its  way  out 
through  the  amniotic  folds,  attaching  itself  to  the  outer  layer  of 
the  amnion  (false  amnion).  In  other  words,  it  becomes  attached  to 
the  chorion,  in  mammals  in  one  spot,  in  birds  all  over  the  chorion. 

What  is  formed  at  this  point? 

By  the  interlacing  of  these  vessels  with  those  of  the  mother  the 
placenta  is  developed. 

Of  what  does  the  chorion  now  consist  ? 

Three  layers  :  1st,  the  vitelline  membrane ;  2d,  the  outer  layer 
of  the  amniotic  fold ;  3d,  the  allantois. 

What  are  the  villi  of  the  chorion? 

Small  processes  on  its  surface  which  soon  become  vascular, 
particularly  so  in  the  region  of  the  future  placenta,  so  as  to  dip 
between  the  maternal  vessels. 

What  changes  take  place  in  the  uterine  mucous  membrane 
during  this  time  ? 
The  follicles  become  tortuous  and  enlarged,  while  the  epithe- 
lial layers  increase  in  amount. 


THE    DEVELOPMENT    OF    ORGANS.  179 

What  is  the  result  of  this  increase  in  the  uterine  mucous 
membrane? 
It  makes  up  the  membrana  decidua. 

Into  how  many  divisions  are  the  portions  of  the  membrana 
decidua  divided? 
Three :  The  fccidua  vera,  deci'lmi  reflexa,  and  the  decidua  serotina 

What  is  the  function  of  these  three  divisions  ? 

The  vera  lines  the  cavity  of  the  uterus;  the  reflexa  grows  up 
around  the  ovum  and  forms  an  investment  for  it;  while  tip 
Una  becomes  especially  developed  in  connection  with  the  villi  of 
the  chorion.  Remember,  by  the  third  month  the  vera  and  reflexa 
come  in  contact,  and  can  no  longer  be  distinguished  one  from  the 
other. 

What  is  the  function  of  the  placenta  ? 

It  is  an  organ  by  which  the  gaseous  and  nutritive  changes  take 
place  between  the  maternal  tissues  and  the  embryo. 

The  placenta  has,  therefore,  a  foetal  part  and  a  maternal  part. 

THE   DEVELOPMENT   OF  ORGANS. 

Vertebral  Column  and  Cranium. 

How  are  the  vertebral  column  and  cranium  developed? 

The  notochord  or  chorda  dorsalis  consists  primarily  of  soft  cellu- 
lar cartilage  which  is  gradually  inclosed  in  a  membranous  sheath, 
which  after  a  time  becomes  fibrous  and  has  transverse  annular 
fibres.  The  protovertebrre  (see  page  1~>4)  send  processes  downward 
and  inward  to  surround  the  notochord,  and  also  upward  between 
the  medullary  canal  and  the  epiblast  covering  it.  In  the  former 
situation  the  cartilaginous  bodies  of  the  vertebrae  make  their  ap- 
pearance, in  the  latter  their  arches  which  inclose  the  neural  canal. 
The  vertebrae  do  not  exactly  correspond  in  their  position  with  the 
protovertebrre,  but  each  permanent  vertebra  is  developed  from  the 
contiguous  halves  of  the  protovertebrae. 

The  cranium  is  developed  from  a  prolongation  of  the  vertebral 


180         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

column,  and  is  formed  long  before  the  facial  bones.  It  is  formed 
of  one  mass,  the  cerebral  capsule,  the  chorda  dorsalis  being  con- 
tinued into  its  base  and  ending  there  with  a  tapering  point. 

In  what  way  is  the  dorsal  portion  of  the  body  formed  ? 

The  muscles  and  iutegument  of  the  back,  with  the  exception  of 
the  epiderm,  which  is  developed  from  the  epiblast,  are  developed 
from  the  musculo-cutaneous  plate  which  is  formed  by  the  dorsal 
portion  of  the  protovertebrse. 

What  is  developed  from  the  ventral  portion  of  the  proto- 
vertebrse ? 

They  give  rise  to  the  vertebne  and  the  heads  of  the  ribs,  but  the 
outer  part  of  each  protovertebra  gives  rise  to  a  spinal  ganglion  and 
nerve-root. 

What  is  the  condition  at  this  time  of  the  chorda? 

It  is  inclosed  in  a  case,  formed  by  the  bodies  of  the  vertebrae,  and 
gradually  wastes  and  disappears. 

How  are  the  body  cavities  formed? 

The  dorsal  lamince  coalesce  at  the  back  and  complete,  by  their 
union,  the  spinal  canal,  and  the  visceral  laminae  coalesce  anteriorly 
and  thus  form  the  thoracic  and  abdominal  cavities.  An  analogous 
process  occurs  in  the  facial  and  cervical  regions,  but  the  inclosing 
laminae  are  cleft.  When  these  clefts  fail  to  unite  in  the  median 
line  cleft-palate  or  harelip  results. 

Extremities- 

In  what  way  are  the  extremities  developed  ? 

They  appear  in  the  form  of  leaf-like  elevations  from  the  parietes 
of  the  trunk  at  points  where  more  or  less  of  an  arch  will  be  pro- 
duced for  them  within. 

Heart  and  Bloodvessels. 

How  is  the  heart  developed  ? 

It  makes  its  first  appearance  as  a  solid  mass  of  cells  of  the 
splanchnopleure.      A  cavity  is  hollowed  out  of  the  centre,  and 


THE    DEVELOPMENT    OF    ORGANS.  181 

those  detached  cells  float  about  in  a  liquid  which  boob  begins  to 

move  about  under  the  pulsations  of  the  embryonic  heart. 

How  are  the  bloodvessels  developed  ? 

In  the  formation  of  the  Large  vessels  masses  of  embryonic  cells 
are  arranged  in  Longitudinal  form  and  hollowed  out  in  much  the 

same  manner  as  the  heart,  the  cells  of  the  heart  cavity  and  blood- 
vessel cavities  forming  corpuscles.  The  capillaries  seem  to  be 
formed  of  cells  arranged  end  to  end  in  single  line  and  hollowed 
like  a  pipe-stem. 

Nervous  System. 

How  is  the  nervous  system  developed  ? 

All  the  spinal  nerves  are  derived  from  the-  mesoblast,  as  are  also 
the  cranial  nerves,  except  the  optic  and  olfactory,  which  are  out- 
growths of  the  anterior  cerebral  vesicles.  The  sympathetic  system 
is  also  developed  from  the  same  mesoblastic  layer. 

Have  the  spinal  cord  and  brain  the  same  origin  as  the 
spinal  nerves  ? 
Yes.     They  arise  from  the  epiblast  for  the  gray  matter  and  for 
the  white  matter. 

From  what  is  the  spinal  cord  developed  ? 

Out  of  the  primitive  medullary  tube  which  results  from  the 
folding  in  of  the  dorsal  laminae. 

How  is  the  gray  matter  formed  ? 

The  tube  is  narrowed  in  one  diameter  so  that  the  canal  becomes 
narrow  and  oval  in  shape,  and  finally  the  two  opposite  sides  unite 
in  the  centre  of  the  slit,  while  the  attachments  of  the  two  sides  at 
the  top  and  bottom  of  the  canal  decrease  in  thickness,  and  finally 
separate.  The  white  matter  is  derived  from  the  surrounding  meso- 
blasl  and  grows  up  around  the  gray  columns.  The  tissnres  are 
formed  by  the  separating  at  the  top  and  bottom  of  the  tube  already 
described. 

What  do  you  mean  by  the  cerebral  vesicles  ? 

A  widening  out  of  the  medullary  canal  very  early  in  embryonic 
life. 


182         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

How  many  cerebral  vesicles  have  we? 
Three. 

What  is  the  purpose  of  each  ? 

From  the  first  anterior  vesicle  are  budded  off  the  two  primary 
optic  vesicles,  and  the  rudiments  of  the  hemispheres  appear  in  the 
form  of  two  outgrowths  at  a  higher  level.  The  middle  vesicle 
gives  off  the  rudiments  of  the  corpora  quadrigemina,  the  crura 
cerebri,  and  the  aqueduct  of  Sylvius.  The  posterior  vesicle  gives 
off  the  rudiments  of  the  cerebellum,  pons  Varolii,  the  medulla 
oblongata,  and  auditory  nerve. 

Eye. 

From  what  is  the  eye  developed  ? 

The  anterior  cerebral  vesicle,  which  sends  out  a  smaller  vesicle 
on  each  side,  the  primary  optic  vesicles,  which  are  hollow.  The 
stalks  which  attach  the  vesicles  to  the  original  vesicle  form  the 
optic  nerves.  After  this  the  formation  of  the  lens  and  optic  cups,  or 
secondary  optic  vesicles,  begins. 

How  is  the  lens  formed  ? 

By  a  thickening  of  the  epiblast,  which  indents  the  extremity  of 
the  primary  optic  vesicle  and  pushes  it  back  till  the  front  wall  of 
the  vesicle  is  in  contact  with  the  posterior  wall,  and  the  cavity  of 
the  vesicle  is  thereby  obliterated. 

What  does  this  front  wall,  which  has  been  pushed  back, 
form  ? 
The  retina. 

What  does  the  back  wall  form? 

The  pigment  layer  of  the  choroid. 

The  margins  of  the  cups  grow  up  around  the  lens  everywhere 
except  at  the  lower  part,  by  the  optic  nerve,  where  a  fissure 
remains. 

What  is  this  fissure  called  ? 
The  choroidal  fissure. 


THE    DEVELOPMENT    OF    ORGAN'S  183 

What  is  its  purpose  ? 

Through  it  the  mesoblast,  which  forms  the  connective  tissue  of 
the  eye,  finds  an  entrance  into  the  cavity  of  the  eye. 

Ear. 

How  is  the  ear  developed  ? 

Early  in  embryonic  life  a  depression  occurs  on  each  side  of  the 
surface  of  the  head,  which  is  covered  by  a  membrane,  the  primary 
otic  vesicle. 

What  is  the  purpose  of  this  vesicle? 

It  develops  the  membranous  labyrinth  of  the  internal  ear.  The 
surrounding  mesoblast  gives  rise  to  the  various  bony  and  carti- 
laginous parts  inclosing  the  membranous  labyrinth,  the  bony 
semicircular  canals,  etc.  The  mesoblast  also  develops  the  auditory 
nerve. 

Nose. 

How  is  the  nose  developed  ? 

It  originates,  like  the  eyes  and  ears,  in  a  depression  of  the 
superficial  epiblast  at  each  side  of  the  fronto-nasal  process,  and 
these  cavities  gradually  grow  hack  till  they  reach  the  cavity  of  the 
mouth. 

Alimentary  Canal  and  Organs. 

In  what  way  is  the  alimentary  canal  developed  ? 

It  results  from  the  folding  in  of  the  splanchnopleure,  and  is  at 
first  straight  and  parallel  to  the  vertebral  column.  It  is  connected 
with  the  omphalo-mesaraic  duct,  a  point  which  corresponds  with 
the  lower  segment  of  the  ileum,  but  the  duct  atrophies  and  usually 
disappears  about  the  fourth  month.  The  attachment  is  at  first 
very  broad,  and  only  a  thin  stratum  of  mesoblast  separates  the 
hypoblast  of  the  canal  from  the  uotochord  and proto vertebrae ;  but 
it  subsequently  attenuates  and  becomes  the  mesentery.  In  the 
fourth  month  the  part  connected  with  the  umbilical  vesicle  loops 
forward.       The  part  above  the   umbilical  opening  becomes  the 


184         ESSENTIALS    OF    HUMAN    PHYSIOLOGY. 

small  intestine,  and  the  part  below  almost  wholly  the  large  in- 
testine. The  limit  between  the  two  is  soon  indicated  by  a 
projection,  the  caecum.  The  intestine  separates  from  the  abdominal 
wall,  the  remains  of  the  attachment  appearing  at  the  third  month, 
and  sometimes  later,  as  a  thread-like  appendage  to  the  lower  part 
of  the  ileum.  Convolutions  then  begin  to  form,  and  an  enlarge- 
ment in  the  region  of  the  liver,  which  is  the  stomach. 

In  what  way  is  the  posterior  opening  in   the   intestine 
formed  ? 

By  the  establishment  of  a  communication  between  the  cloaca,  or 
tube  common  to  the  gut  and  allantois,  and  a  depression  outside  of 
the  body  at  about  the  sixth  or  seventh  week.  At  the  same  time  a 
septum,  which  is  the  future  perineum,  separates  the  intestine  from 
the  organs  forming  the  allantois.  The  mouth  is  formed  in  the 
same  manner. 

In  what  way  are  the  salivary  glands,  the  pancreas,  and 
the  liver  developed? 
The  liver  commences  as  a  projection  formed  by  two  primitive 
hepatic  ducts,  which  divide  and  subdivide.  At  the  periphery  of 
the  ducts  are  solid  masses  of  cells  which  proceed  from  the  hypo- 
blast. The  mass  of  the  gland  is  developed  from  the  mesoblast. 
The  liver  secretes  as  early  as  the  third  month.  The  pancreas  is 
also  formed  from  the  mesoblast,  as  are  also  the  salivary  glands. 
The  lining  of  their  ducts  is,  however,  derived  from  the  hypoblast. 

The  Foetal  Circulation. 

Describe  the  foetal  circulation  ? 

The  blood  in  the  placenta,  aerated  and  well  nourished,  passes 
up  the  umbilical  vein  to  the  navel,  where  it  enters  the  body  of  the 
foetus,  and,  after  a  short  course,  reaches  the  liver,  where  it  is  split  up 
into  two  streams,  one  of  which  supplies  the  lobes  of  the  liver,  while 
the  other  passes  through  the  ductus  venosus,  which  lies  in  the  longi- 
tudinal fissure  of  the  liver,  into  the  inferior  vena  cava  and  right 
auricle  of  the  heart,  but  instead  of  passing  into  the  right  ventricle 
it  is  directed  by  the  Eustachian  valve  along  the  back  of  the  auricle 


THE     DEVELOPMENT    OF    ORGAN'S.  L85 

to  the  foramen  ovale,  and  immediately  enters  the  left  auricle;  the 
left  auricle,  contracting,  propels  it  into  the  left  ventricle,  which 
drives  it  into  the  general  circulation. 

What  is  the  difference  in  the  circulation  of  blood  in  the 
inferior  vena  cava  from  that  of  the  superior  vena 
cava? 

The  blood  returning  from  the  head,  or  superior  vena  cava,  | 
into  the  right  auricle  and  enters  the  right  ventricle  (which  the 
blood  from  the  inferior  vena  cava  does  not).  When  the  right 
ventricle  contracts  the  blood  is  driven  into  the  pulmonary  artery, 
but  instead  of  being  distributed  through  the  lungs  it  is  directed 
through  a  channel  given  off  by  the  left  pulmonary  artery,  known 
as  the  ductus  arteriosus,  into  the  aorta  just  beyond  the  point  where 
the  left  subclavian  is  given  off  from  that  vessel.  The  right  ventricle 
and  the  left  ventricle  may,  therefore,  be  said  to  drive  the  blood 
through  the  general  circulation  in  fcetal  life.  As  the  result  of  this, 
however,  it  will  be  seen  that  in  the  aorta  we  have  blood,  half  of 
which  is  aerated  and  halfof  which  is  not. 

In  what  way  does  the  blood  return  to  the  placenta  to  be 
nourished  and  oxygenated  ? 

It  passes  through  the  descending  aorta,  the  common  iliacs,  and 
the  umbilical  artery,  by  which  it  reaches  the  placenta. 

What  changes  take  place  in  the  circulation  at  birth  ? 

Respiration  is  commenced,  the  lungs  become  expanded,  and.  in 
consequence  of  this,  the  pulmonary  vessels  permit  the  blood  to 
traverse  them  freely.  The  ductus  arteriosus  being  no  longer 
required,  contracts  and  shrivels  up,  but  remains  as  a  fibrous  cord. 
At  the  same  time  the  detachment  of  the  placenta  leads  to  the  im- 
mediate arrest  of  the  flow  of  blood  from  the  umbilical  arteries,  and 
no  flow  passes  along  the  umbilical  vein.  The  ductus  renosus 
contracts,  the  currents  of  the  superior  and  inferior  vena  cava  mix 
in  the  right  side  of  the  heart,  and  the  Eustachian  valve  and  the 
foramen  ovale  become  useless. 


INDEX. 


ABDUCENT  nerve,  143 
Aberration,  chromatic,  156 

Absorption,  73 

Accelerator  ganglion  of  the  heart,  37 
nerve,  38 

Accommodation  of  eye,  155 

Acid-albumin,  20 

Action  of  muscles,  104 

Afferent  nerves,  114 

Agrammatism,  165 

Albumen,  19 

Albuminous  foods,  102 

Alimentary  canal,  development  of, 
176,  183 

Alkali-albumin,  20 

Allantois,  178 

Amnesic  aphasia,  165 

Amnion,  177 

Amylolopsin,  67 

Anfemia,  30 

Anelectrotonus,  115 

Animal  heat,  76 

source  of,  77 

Anterior  columns,  119 

Aperistalsis,  65 

AphEemia,  165 

Aphasia,  164 

Aphonia,  164 

Apncea,  53 

Appendages  of  the  skin, 97 

Aqueous  humor,  154 

Area  opaca,  175 
pellucida,  174 

Argyll  Robinson  pupil,  158 

Arteries,  40 

Arterioles,  46 

Arytenoid  cartilages,  162 

Asphyxia,   influence    of,   on    blood- 
pressure,  44 

Astigmatism,  156 

Auditory  canal,  159 
nerve,  143 


Auricles  of  the  heart,  31 
functions  of,  32 
Auriculo-ventricular  valves,  33 
Automatism,  124 
Axis  cylinder,  112 


BILE,  71 
acids,  71 

pigments,  71 
Bipolar  cells,  119 
Bizzozero,  blood  plaque  of,  24 
Bladder,  88 
Blastoderm,  174 
Blind  spot,  153 
Blood,  the,  21 

coagulation  of,  28 

pressure,  42 
Bloodvessels,  39 

of  brain,  136 

development  of,  181 
Body  cavity,  176 
Boundary  zone  of  kidney,  81 
Brain,  weight  of,  135 
Bronchial  veins,  49 
Buffy  coat,  30 
Burdach's  column,  120 

CALCIUM  phosphate  in  milk,  102 
Calyx  of  kidney,  83 
Capacity  of  the  parts  of  the  vascular 

system,  42. 
Capillaries,  39 
Carbohydrates,  20 
Carbonic  dioxide,  51 
Cardiac  nerves,  38 

veins,  34 
Casein,  20 

Cavities  of  the  heart,  31 
Centre  for  deglutition,  131 
for  respiration,  131 


INDEX. 


187 


Centre  for  urination,  89 

for  vomiting,  131 

inhibitory,  131 

vasomotor,  l".l 
Centrifugal  nerves,  1 13 
Centripetal  nerves,  113 
Cerebellar  tract,  124 
Cerebellum,  135 
Cerebral  localization,  138 
<  lerebrum,  137 
Cerumen,  159 
Cervical  sympathetic,  1 66 
Chemical  basis  of  the  body,  17 

changes  in  muscles,  109 

composition  of  the  liver,  72 
Chiasm,  optic,  141 
Cholesterin,  71 
Choluria,  94 
Chorda  dorsalis,  175 

tympani  nerve,  56 
Chorda  tendinea?,  -".4 
Chorion.  177 
Choroid  coat,  151 
Chromatic  aberration,  156 
Chyluria,  94 
Chyme,  63 
Ciliary  muscle,  151 

processes,  151 
Cilio-8pinal  centre,  131 
Circulation,  35 

through  heart,  35 
Classification  of  proteids,  19 
Coagulation  of  the  blood,  28 
of  the  arteries,  40 

of  the  eye,  149 
Color-blindness.  I".ii 
Color  of  the  bile,  71 

of  the  blood,  22 

of  the  urine,  91 
Colostrum,  101 
Columns  carnese,  35 
Columns  of  the  spinal  cord,  118 
Colloids  75 
Complemental  air,  50 
Course  of  the  medullary  fibres,  11s! 
Cones  of  the  eye,  153 
Consciousness,  137 
i  ionsistency  of  muscle,  105 
Constituents  of  the  bl 1,  23 

of  milk,  102 
Contraction  of  muscles,  99 
Convolutions  of  brain,  138 
Cornea,  1  .">  1 
Coronary  arteries,  34 


Corpora  quadrigemina,  133 

striat 
Corpus  luteuru,  171 
Corpuscles,  nerve,  L16,  147 

red  blood,  22 
Cortex  of  kidney,  81 
Corti,  organ  of,  1'il 
Coughing,  5  I 

Coverings  of  eye,  l  in 

Cranial  nerves.  1  1 1 

•  Iranium,  development  of,  17'.' 

Cricoid  cartilage,  162 

Crossed  pyramidal  tracts,  120,   122, 

1  2'.) 
Crura  cerebri,  133 

>lline  lens,  154 
Crystalloids 


DECIDUA  menstruaJis,  170 
refiexa,  1  7'.» 

serotina,  179 

vera,  179 
Decussation,  12'.» 
Defibrmated  blood,  29 
Definition  of  physiology,  17 
Deglutition,  .">'.>.  131 
Depressor  nerves, 
Development,  173 

of  organs,  1 7'.i 
Diabetes  insipidus,  94 

mellitus,  94 
Diapedesis,  24 

Diastatic  action  of  saliva,  ">.">,  58 
Diffusion,  7  1 
Digestion.  .">  1 
Dioptric  media,  158 
Diplopia.   156 
Direct  cerebellar  tract,  124,  130 

pyramidal  trad-.  120,  122.  L29 
Discus  proligerus,  169 
Ductus  arteriosus,  1 8 1 

venosus,  184 
Dysperistalsis,  65 
Dyspnoea,  53 


[?AK.  development  of.  183 
J     F.tl'erent  nerves,  160 
L02 
Elasticity  of  muscles,  I'"'' 
Electrical  phenomena  of  mm  I 

Electrotonus,  l  l  5 
Endocardium,  32 


188 


INDEX. 


Fmbryonal  heart,  31 

Emmetropia,  157 

Endolymph,  160 

Endosmosis,  73 

Entopic  images,  156 

Epiblast,  174 

Epididymis,  172 

Epiglottis,  164 

Euperistalsis,  65 

Eupncea,  53 

Eustachian  tube,  160 

Excretion,  97 

Expiration,  49 

External  ear,  160 

Extremities,  development  of,  179 

Extrinsic  cardiac  nerves,  38 

Eye,  149 

development  of,  182 
Eyeball,  150, 
Eyelashes,  149 


FACIAL  nerve,  143 
Falling  energy,  110 
Fallopian  tubes,  169 
Far  point,  155 
Fats,  21,  102 
Feces,  amount  of,  72 
Fecundation,  173 
Fibrin,  20,  28 
Fibrin-ferments,  28 
Fibrinogen,  19 
Fibrinoplastin,  28 
Filtration,  74 
Flesh,  94 

Foetal  circulation,  184 
Fourth  ventricle,  129 
Functions  of  the  bladder,  88 

of  the  blood,  21 

of  the  coats  of  the  arteries,  40 

of  the  gray  matter  of  cord,  122 
if  the  heart,  32 

of  the  kidneys,  81 

of  the  liver,  71 

of  the  skin,  95 

of  tracts  of  cord,  122 

of  the  white  matter  of  cord,  122 

of  the  cardiac  valves,  33 


GANGLION  of  the  heart,  35 
Gases  of  the  blood,  27 
of  the  stomach,  63 
Gastric  digestion,  62 


Gastric  juice,  62 

Gelatinous  substance  of  Rolando,  120 

Generation,  167 

Generative  organs  of  female,  168 

of  male,  171 
Germinal  area,  174 

vesicle,  169 
Globulins,  19 
Glomerulus,  84 
Glosso-pharyngeal  nerve,  143 
Glycogen,  70 
Glycosuria,  94 
Goll's  column,  122 
Graafian  vesicles,  168 
Gray  matter  of  cord,  118 


H^MATIN,  27 
Haemoglobin,  27 
Harmoglobinuria,  94 
Hair,  97 
Head  folds,  176 
Hearing,  158 
Heart,  the,  31 

development  of,  189 

embryonal,  31 

weight  of,  31 

sounds  of,  36 

suction  of,  32 

valves  of,  33 
Heat,  animal,  76 

dissipation,  78 

production,  78 
Heintz's  test,  71 
Hemianopsia,  157 
Hiccough,  54 
Hippuric  acid,  93 
Humors  of  the  eye,  154 
Hypermetropia,  157 
Hypoblast,  1 74 
Hypoglossal  nerve,  144 


Indifferent  point,  ne 

1      Indol,  67 
Inhibitory  centre,  131 

ganglion  of  the  heart,  35 
Injuries  of  optic  nerve,  141 
Inspiration,  49 
Intestinal  digestion,  66 
Inversion  of  images,  154 
Iris,  152 
Irritability  of  muscle,  107 


INDEX. 


189 


KATELECTROTONUS,  [15 
Kidneys,  81 
Kinetic  energy,  99 
Kreatin  and  kreatinin,  106 


LABYRINTH  of  kidney.  B2 
Lachrymal  glands,  149 
l.s,  74 
Lactic  acid,  62 
Lactiferous  ducts,  98 
Laminae  dorsalis,  175 
Large  intestine,  function  of,  72     . 
Larynx,  162 

muscles  of,  1 62 
Latent  period,  1  lit 

-I  columns  of  spinal  cord,  120 
Laughing,  54 

Laws  of itracl  ion,  l  L6 

Laxator  tympani  muscle,  160 

Left  heart,  31 

Lens,  154 

Lesions  of  spinal  cord,  127 

Leucin,  67 

Leucocythamia.  "ill 

Ligation  of  coronary  arteries,  34 

Liquor  amnii,  17s 

Liver,  68 

Locus  niger,  132 


MACULA  lutea,  153 
Male  sexual  organs,  150 
Malpighiaa  body,  83 
Maltose,  55 
Mammary  glands,  98 
Masl  ication,  59 
Maximum  stimulation,  110 

contraction,  111 
Medulla  of  kidney,  81 

oblongata,  128 
Medullary  grooye,  175 
Meibomian  glands,  1 1'.l 
Meissner's  plexus,  64 
Membrana  decidua,  I  79 
Membranes  of  brain  and  cord,  1 1 8 
Menstruation,  170 
Mesoblast,  174 
Metabolism,  98 
M  icrocytes,  24 
Milk,  98 

Milk-curdling  ferments,  63,  67 
Milk  globules,  100 

plasma,  100 


Millon's  reagent,  20 

[anglion  of  the  heart,  37 

nerve-,   I  I  I 
Movements  of  respiration,  49 

of  I  lie  heart,  .'!5 

of  the  stomach,  60 
Multipolar  cells,  1  19 
Muscle,  ciliary,  I  19 

laxator  tympani,  I 'ill 

plasma,  105 

>r  tympani,  160 
Muscles,  104 

of  larynx,  163 
Musculi  papillares,  35 
Myopia,  157 
Myosin,  19,  105 


NAILS,  97 
Near  point,  155 
Negative  variation,  H>7,  114 
Neural  cavity,  17i> 
Nerve,  abducent,  143 

auditory,  143 

corpuscles,  116 

facial,  14:; 

glosso-pharyngeal,  143 

hypoglossal,  1  11 

oculo- motor,  141 

olfactory,  141 

pathetic,  142 

pneumogastric,  1  1 1 

spinal  accessory,  I  1 1 

sublingual,  144 

sympathetic,  165 

vagus,  1  14 
Nerves  of  the  kidney,  87 

of  special  sense,  145 

of  the  stomach,  02 

of  taste,  147 
Nervi  nervorum,  I  12 
Nervous  mechanism  of  deglutition 
60 
of  the  heart,  37 

of  heal.  7S 

of  respiration,  53 

of  speech,  163 

of  urinatioi 
Nervous  system,  112 

development  of,  181 
Neuroglia,  118 
Nose,  developmenl  of,  •■ 
Nbtochord,  175 
Number  of  heart  valves,  33 


190 


INDEX. 


Nourishment  of  heart,  34 
Nystagmus,  158 

OBJECT  of  respiration,  48 
Oculo-motor  nerve,  141 
Odor  of  the  blood,  22 
Olfactory  nerve,  141 
Olivary  body,  129 
Optic  chiasm,  141 

lobes,  133 

nerve,  141 

thalami,  133 
Organ  of  Corti,  161 
Organs  of  generation,  168 
Otoliths,  160 
Ovaries,  168 
Ovule,  169 
Ovum,  170 
Oxyhemoglobin,  22 


PANCREATIC  digestion,  66 
ferments,  67 
Papillae  of  the  skin,  95 
Paraglobulin,  19 
Parapeptone,  63 
Paraphasia,  165 
Parotid,  55 

Parts  of  the  kidney,  86 
Pathetic  nerve,  142 
Pepsin,  62 
Peptones,  19 
Pericardium,  36 
Peristalsis,  64 
Perspiration,  79 

function  of,  79 
Pettenkofer's  test,  71 
Physical  forces  of  the  circulation,  45 
Physiology  of  the  spinal  nerves,  117 
Placenta,  179 
Plasma,  blood,  23 

milk,  100 

muscle,  105 
Plethora,  30 

Pneumogastric  nerve,  38,  144 
Pons  Varolii,  133 

Posterior  columns  of  spinal  cord,  119 
Presbyopia,  157 
Pressor  fibres,  39 
Primitive  fibril,  112 
Primitive  groove,  175 
Processes,  ciliary,  151 
Prostate  gland,  173 


Proto  vertebrae,  175 
Proteids,  18 
Ptyalin,  58 
Pulse,  47 

rapidity  of,  37 
Pupil,  152 

Pupillary  movement,  152 
Pyramids  of  kidney,  83 

of  medulla  oblongata,  128 


QUADRIGEMINAL  bodies,  133 
•    Quantity  of  the  bile,  72 
Quantity  of  the  blood,  28 
of  blood  expelled,  35 
of  the  saliva,  55 


RAMI  communicantes,  165 
Ranvier's  nodes,  112 
Rate  of  the  heart,  37 

of  respirations,  51 
Reaction  of  muscles,  109 

of  the  blood,  22 

of  the  urine,  91 
Recurrent  sensibility,  117 
Reflex  action,  124 

inhibiting  centre,  126 
Refraction,  155 
Reserve  air,  50 
Residual  air,  50 
Respiration,  48 
Respiratory  centre,  53,  131 
Restiform  bodies,  117 
Retina,  153 
Right  heart,  31 
Rising  energy,  110 
Ritti-Valli  law,  118 
Rods  of  eye,  153 

Rolando,  gelatinous  substance  of,  120 
Roots  of  trifacial  nerve,  142 
Rouleaux,  25 


SALIVA,  54 
Salivary  centre,  120 
digestion,  54 
glands,  54 
Salts,  94 

of  urine,  93 
Sclerotic  coat,  150 
Sebaceous  glands,  97 
Secretion,  97 


INDEX. 


191 


Section  of  vagi,  39 
Segmentation  of  ovum,  17.''. 
Semen,  172 

Semicircular  canals,  160 
Semilunar  valves,  33 
Sense  of  sight,  149 

of  smell,  148 

of  taste,  147 

of  touch,  146 
Sensibility,  146 
Sensory  nerves,  114 
Serum,  blood,  23 
Setschenow's  centre,  131 
Sighing,  54 
Bight,  149 

Size  of  the  kidneys,  81 
Skatol,  67 
Skin,  95 

Smell,  sense  of,  148 
Sneezing,  54 
Sobbing,  54 
Somatopleure,  176 
Sounds  of  the  heart,  36 
Source  of  animal  heat,  76 
Special  sense.-.  I  45 
Specific  gravity  of  the  blood,  23 
of  milk,  98 
of  urine,  90 
Speech,  161 

centre,  138 
Speed  of  the  circulation,  48 
Spermatozoids,  1 72 
Spherical  aberration,  156 
Spinal  accessory  nerve,  144 

nerves,  ID 7 
Splanchnic,  167 

Splanchnics,  influence  of,  on  peristal- 
sis, 65 
Splanchnopleure,  176 
Stapedius  muscle,  158 
Starch,  20 
Starches,  102 
Starvation,  103 
Steapsin,  68 
Stimulation  <>f  vagus  nerves,  38 

of  accelerator  nerves,  39 
Stomach,  60 
Sublingual  nerve,  144 

saliva,  55 
Submaxillary  saliva,  55 
Suction  power  of  heart,  32 
Sudoriferous  gland-.  96 
Sugar,  20 
Summation,  111 


96 

Sympathetic,  56 
nerve,  165 


TACTILE  sensibilitv,  146 
Tail  folds,  176 
Taste,  147 

buds,  147 

goblet-    1  17 

nerves  of,  I  18 

of  the  blood,  23 
Temperature  of  the  blood,  23 
Tensor  tympani  muscle,  160 
Testicles,  171 
Tests  for  proteids,  20 
Tetanus,  1 1 1 
Thyroid  cartilage,  162 
Tidal  air,  50 

Tractus  intermedio-lateralis,  119 
Transference,  1L'4 
Trifacial  nerve,  142 
Trammer's  test,  21 
Trypsin,  67 

Fallopian,  168 
Tubuli  seminiferi,  172 

uriniferi,  83 
Tiirck's  columns,  122 
Tympanic  membrane,  159 
Tyrosin,  67 

UMBILICAL  veins,  185 
vesicle,  176 
Unipolar  cell,  119 
Urea,  92 
Ureters,  87 
Uric  acid,  93 

Urinse  potus,  cibi,  and  sanguinis,  yi 
Urine,  90 
Uterus,  168 

VAGINA,  168 
Vagus  nerve,   18,  lit 
Valves  of  the  heart,  .'j:; 

of  the  vein-.  1 1 
Variations  in  the  blood,  23 
Vasa  recta,  86 
Vas  deferens,  172 
Vasomotor  centre,  43,  131 

nerves,  43 
Vegetable  foods,  102 
Veins,  37 

card: 


192 


INDEX, 


Ventricles  of  the  heart,  31 

weight  of,  31 
Vernix  caseosa,  97 
Vertebrae,  development  of.  1 79 
Vesiculre  seminales,  172 
Vesicular  columns  of  Clark,  119 
Visceral  plates,  176 
Visual  purple,  154 
Vital  capacity,  50 
Villi  of  chorion,  178 
Villus,  74 
Vitellin,  19 

Vitelline  membrane,  177 
Vitreous  humor,  154 
Voice,  161 
Vomiting,  64 

centre,  131 


WATER,  91,  94 
Weight  of  brain,  135 
of  heart,  31 
of  left  ventricle,  31 
"White  blood- corpuscles,  24 

matter  of  the  spinal  cord,  118 
Work  of  respiratory  muscle,  51 


V  ANTHO-PROTEIC  reaction,  20 
70NApellucida,  169 


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•American  Text- Hook  of   Applied   Thera- 
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'American  Text- Hook  of  Dis.  of  Children  .  9 
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Eye,  Ear,  Nose,  and  L'hroat 31 

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Ashton's  Obstetrics 28 

Atlas  of  Skin  Diseases 12 

Ball's  Bacteriology 28 

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Brockway's  Physics 28 

Burr's  Nervous  Diseases 26 

Butler's  Materia  Medica  and  Therapeutics  29 
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Chapman's  Medical  Jurisprudence  .    .   .    .  26 
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Clarkson's  Histology 14 

Cohen  and  Eshner's   Diagnosis 28 

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Cragin's  Gynaecology 28 

-hank's   Text-Hook  of  Bacteriology  .  13 

DaCosta's  Manual  of  Surgery 26 

De  Schweinitz's  Diseases  of  the  Eye  ...  15 

Dorland's  Obstetrics     26 

Frothingham's  Bacteriological  Guide  ...  16 

Garrigues'  Diseases  of  Women 20 

Gleason's  Diseases  of  the  Ear 28 

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Griffin's  Materia  Medica  and  Therapeutics  26 

Griffith's  Care  of  the  Baby 24 

(  in^'s  Autobiography 10 

Hampton's  Nursing 23 

Hare's  Physiol. igy      .'8 

Hart's  Diet  in  Sickness  and  in  Health    .    .  22 

Haynes'  Manual  of  Anatomy 26 

Heisler's  Embryology 31 

Hirst's  Obstetrics 31 

Hyde's  Syphilis  and  Venereal  Diseases  .  .  26 
Jackson  and  Gleason's  Diseases  of  the  Eye, 

Nose,  and  Throat 28 

Jewett's  Outlines  of  Obstetrics 21 

Keating's  Pronouncing  Dictionary  ....  10 

Keating' s  Life  Insurance 23 

Keen's  Operation  Blanks 22 

Kyle's  Diseases  of  Nose  and  Throat  .  .  .26 
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ment 31 

McFarland's  Pathog         l            .    .    .   .   .  16 
Mallory  and  Wright's  Pathological  Tech- 
nique   31 

Martin's  Surgery 28 

Martin's    Minor   Surgery,  Bandaging,  and 

Venereal  Diseases 28 

Meigs'  Feeding  in  Early  Infancy 16 

Moore's  Orthopedic  Surgery 31 

Morris'  Materia  Medica  and  'Therapeutics  28 

Morris'  Practice  of  Medicine 28 

Morten's  Nurses' Dictionary 24 

Nancrede's  Anatomy  and  Dissection  ...  17 

Nancrede's  Anatomy 28 

Norris'  Syllabus  of  Obstetrical  Lectures    .  21 

Penrose's  Gynecology 31 

Powell's  Diseases  of  Children 28 

Pye's  Elementary  Bandaging  and  Surgical 

Dressing 29 

Raymond's  Physiology 26 

Rowland's  Clinical  Skiagraphy 14 

Saundby's  Renal  and  Urinary  Diseases  .    .  29 
•Saunders'  American  Year-Book  of  Medi- 
cine and  Surgery 32 

Saunders'  Pocket  Medical  Formulary  .  .  19 
Saunders'  Pocket  Medical  Lexicon  ....  32 
Saunders'  New  Aid  Series  of  Manuals  .  25,  26 
Saunders'  Series  of  Question  Compends  27,  28 

Sayre's  Practice  of  Pharmacy 28 

Semple's  Pathology  and  Morbid  Anatomy  28 
Semple's  Legal  Medicine.  'Toxicology,  and 

Hygiene 28 

Senn's  Genito-Urinary  'Tuberculosis    .    .    .31 

Senn's  Tumors 11 

Senn's  Syllabus  of  Lectures  on  Surgery  .  .  21 
Shaw's  Nervous  Diseases  and  Insanity  .    .  28 

Starr's  Diet- Lists  for  Children 24 

Stelwagon's  Diseases  of  the  Skin 28 

Stengel's  Manual  of  Pathology 26 

Stevens'  Materia  Medica  and  Therapeutics  18 

Stevens'  Practice  of  Medicine 17 

Stewart's  Manual  of  Physiology 21 

Stewart    and    Lawrance's    Medical    Elec- 
tricity      28 

Stoney's  Practical  Points  in  Nursing  .    .    .  1 3 
Sutton  and  Giles' Diseases  ol  Women   .   .26 
Thomas's  Diet-List  and  Sick-Room  I  >ietary24 
Thornton's  Dose- Book  and  Manual  of  Pre- 
scription-Writing    26 

Van  Valzah  and  Nisbet's  Diseases  of  the 

Stomach 

Vierordi  and  Stuart's  Medical  Diagni  sis    .  ta 

Warren's  Surgical  Path.. logy 11 

Wolffs  Chemistry 28 

Wolffs  Examination  of  Urine 28 


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CATALOGUE    OF  MEDICAL    WORKS. 


For  Sale  by  Subscription. 

AN    AMERICAN    TEXT-BOOK    OF    PHYSIOLOGY.      Edited   by 
William    II.   Howell,   Ph.D.,   M.I).,   Professor  of    PI  ,   the 

Johns  Hopkins  University,  Baltimore,  Md.  <  me  handsome  octavo  volume 
of  1052  pages,  fully  illustrated.  Prices:  Cloth,  $6.00  net;  Sheep  or  Half- 
Morocco,  $7.00  net. 

This  work  is  the  most  notable  attempt  yet  made  in  America  to  combine  in 
one  volume  the  entire  subject  of  Human  Physiology  by  well-known  teachers 
who  have  given  especial  study  to  that  part  of  the  subject  upon  which  they  write. 
The  completed  work  represents  the  present  status  of  the  science  of  Physi 
particularly  from  the  standpoint  of  the  student  of  medicine  and  of  the  medical 
practitioner. 

The  collaboration  of  several  teachers  in  the  preparation  of  an  elementary  text- 
book of  physiology  is  unusual,  the  almost  invariable  rule  heretofore  having  been 
for  a  single  author  to  write  the  entire  book.  One  of  the  advantages  to  be  derived 
from  this  collaboration  method  is  that  the  more  limited  literature  necessary  for 
consultation  by  each  author  has  enabled  him  to  base  his  elementary  account 
upon  a  comprehensive  knowledge  of  the  subject  assigned  to  him;  another,  and 
perhaps  the  most  important,  advantage  is  that  the  student  gains  the  point  of  view 
of  a  number  of  teachers.  In  a  measure  he  reaps  the  same  benefit  as  would  be 
obtained  by  following  courses  of  instruction  under  different  teachers.  The 
different  standpoints  assumed,  and  the  differences  in  emphasis  laid  upon  the 
various  lino  of  procedure,  chemical,  physical,  and  anatomical,  should  give  the 
student  a  better  insight  into  the  methods  of  the  science  as  it  exists  to-day.  The 
work  will  also  be  found  useful  to  many  medical  practitioners  who  may  wish  to 
keep  in  touch  with  the  development  of  modern  physiology. 

The  main  divisions  of  the  subject-matter  are  as  follows:  General  Physiology 
of  Muscle  and  Nerve  —  Secretion  —  Chemistry  of  Digestion  and  Nutrition — 
Movements  of  the  Alimentary  Canal,  Bladder,  and  Ureter—  Hlood  and  Lymph 
— Circulation — Respiration— Animal  Heat — Central  Nervous  System  —Special 
Senses  —  Special  Muscular  Mechanisms  —  Reproduction  —  Chemistry  of  the 
Animal   Body. 

CONTRIBUTORS: 
HENRY  P.  BOWDITCH,  M.  D.,  WARREN  P.  LOMBARD,  M.  D., 

Professor  of  Physiology,  Harvard  Medi-  Physiology,  University  of 

cal  School.  Michigan. 

JOHN  G.   CURTIS,  M.  D.,  ORAHAM  TUSK    Ph   D 

Professor  of  Physiology,  Columbia  Uni-  ^ahabi  lusii,  rn.  1;., 

versity,  X.  X.  (College  of  Physicians  'or  ,of  P'»y*ology,   Yale   Medtcal 

and  Surge-  Scnool. 

HENRY  H.  DONALDSON,  Ph.D.,      W.  T.  PORTER,  M.  D., 

Head-Professor    of    Neurology,   Univer-  Assistant  Professor  of  Physiology,  H.<r- 

sity  of  Chicago.  I  Medical  School. 

W.  H.  HOWELL,  Ph  D.,  M  D.  EDWARD  T.  REICHERT.   M.  D., 

Professor  of  Physiology,  Johns  Hopkins  or  of  Physi*  rsity  of 

1  mversity.  Pennsylvania. 

FREDERIC  S.  LEE,  Ph.  D., 

Adjunct  Professor  of  Ph  HENRY  SEWALL,  Ph.  D.,   M.  D.. 

bia    University.    N.    Y.    (College    of  Depart 

Physicians  and  Surgeons).  incut,  University  of  Denver. 


IV.   B.   SAUNDERS' 


For  Sale  by  Subscription. 


AN  AMERICAN  TEXT-BOOK  OF  APPLIED  THERAPEU- 
TICS. For  the  Use  of  Practitioners  and  Students.  Edited  by 
James  C.  Wilson,  M.  D.,  Professor  of  the  Practice  of  Medicine  and  of 
Clinical  Medicine  in  the  Jefferson  Medical  College.  One  handsome  octavo 
volume  of  1326  pages.  Illustrated.  Prices;  Cloth,  $7.00  net;  Sheep  or 
Half- Morocco,  $8.00  net. 

The  arrangement  of  this  volume  has  been  based,  so  far  as  possible,  upon 
modern  pathologic  doctrines,  beginning  with  the  intoxications,  and  following 
with  infections,  diseases  due  to  internal  parasites,  diseases  of  undetermined 
origin,  and  finally  the  disorders  of  the  several  bodily  systems — digestive,  re- 
spiratory, circulatory,  renal,  nervous,  and  cutaneous.  It  was  thought  proper  to 
include  also  a  consideration  of  the   disorders  of  pregnancy. 

The  list  of  contributors  comprises  the  names  of  many  who  have  acquired  dis- 
tinction as  practitioners  and  teachers  of  practice,  of  clinical  medicine,  and  of 
the  specialties. 

CONTRIBUTORS : 


Dr.  I.  E.  Atkinson,  Baltimore,  Md. 
Sanger  Brown,  Chicago,  1(1. 
John  B.  Chapin,  Philadelphia,  Pa. 
William  C.  Dabney,  Charlottesville,  Va. 
John  Chalmers  DaCosta,  Philada.,  Pa. 
I.  N.  Danforth,  Chicago,  111. 
John  L.  Dawson.  Jr.,  Charleston,  S.  C. 
F.  X.  Dercum,  Philadelphia.  Pa. 
George  Dock,  Ann  Arbor,  Mich. 
Robert  T.   Edes,  Jamaica  Plain,  Mass. 
Augustus  A.  Eshner,  Philadelphia,  Pa. 
J.  T.  Eskridge,  Denver,  Col. 
F.  Forchheimer,  Cincinna'i,  O. 
Carl  Frese,  Philadelphia,  Pa. 
Edwin  E.  Graham,  Philadelphia,  Pa. 
John  Guiteras,  Philadelphia.  Pa. 
Frederick  P.  Henry,  Philadelphia,  Pa. 
Guy  Hinsdale,  Philadelphia,  Pa. 
Orville  Horwitz,  Philadelphia,  Pa. 
W.  W.  Johnston,  Washington,  D.  C. 
Ernest  Laplace,  Philadelphia,  Pa. 
A.  Laveran,  Paris,  France. 


Dr.  James  Hendrie  Lloyd,  Philadelphia,  Pa. 
John  Noland  Mackenzie,  Baltimore,  Md. 
J.  W.  McLaughlin,  Austin,  Texas. 
A.  Lawrence  Mason,  Boston,  Mass. 
Charles  K.  Mills,  Philadelphia,  Pa. 
John  K.  Mitchell,  Philadelphia,  Pa. 
W.  P.  Northrup,  New  York  City. 
William  Osier,  Baltimore,  Md. 
Frederick  A.  Packard,  Philadelphia,  Pa. 
Theophilus  Parvin,  Philadelphia,  Pa. 
Beaven  Rake,  London,  England. 
E.  O.  Shakespeare,  Philadelphia.  Pa. 
Wharton  Sinkler,  Philadelphia.  Pa. 
Louis  Starr,  Philadelphia,  Pa. 
Henry  W.  Stelwagon,  Philadelphia,  Pa. 
James  Stewart,  Montreal.  Canada. 
Charles  G.  Stockton,  Buffalo,  N.  Y. 
James  Tyson,  Philadelphia,  Pa. 
Victor  C.  Vaughan,  Ann  Arbor,  Mich. 
James  T.  Whittaker,  Cincinnati,  O. 
J.  C.  Wilson,  Philadelphia,  Pa. 


The  articles,  with  two  exceptions,  are  the  contributions  of  American  writers. 
Written  from  the  standpoint  of  the  practitioner,  the  aim  of  the  work  is  to  facili- 
tate the  application  of  knowledge  to  the  prevention,  the  cure,  and  the  allevia- 
tion of  disease.  The  endeavor  throughout  has  been  to  conform  to  the  title  of 
the  book — Applied  Therapeutics — to  indicate  the  course  of  treatment  to  be 
pursued  at  the  bedside,  rather  than  to  name  a  list  of  drugs  that  have  been  used 
at  one  time  or  another. 

While  the  scientific  superiority  and  the  practical  desirability  of  the  metric 
system  of  weights  and  measures  is  admitted,  it  has  not  been  deemed  best  to 
discard  entirely  the  older  system  of  figures,  so  that  both  sets  have  been  given 
where  occasion  demanded. 


CATALOGUE    OF  ME  PICA  I.    WO  A' AS. 

For  Sale  by  Subscription. 


AN    AMERICAN     TEXT-BOOK    OF    OBSTETRICS.     Edited   by 
Richard  C.  Norris,  M.  I>.  ;  Art  Editor,  RoBERl   L.  DICKINSON,  M.  I> 

One  handsome  octavo  volume  of  over  iooo  pages,  with  nearly  900  colored 
and  half-tone  illustrations.      Prices:  i  o;  Sheep  or  Half- Morocco, 

$8.00. 

The  advent  of  each  successive  volume  of  the  series  of  the  American  Text- 
Books  has  been  signalized  by  the  most  flattering  comment  from  both  the  Press 
and  the  Profession.  The  high  consideration  received  by  these  text-books,  and 
their  attainment  to  an  authoritative  position  in  current  medical  literature,  have 
been  matters  of  deep  international  interest,  which  finds  its  fullest  expression  in 
the  demand  for  these  publications  from  all  parts  of  the  civilized  world. 

In  the  preparation  of  the  "AMERICAN  TEXT-BOOK  OF  OBSTETRICS"  the 
editor  has  called  to  his  aid  proficient  collaborators  whose  professional  prominence 
entitles  them  to  recognition,  and  whose  disquisitions  exemplify  Practical 
Obstetrics.  While  these  writers  were  each  assigned  special  themes  for  dis- 
cussion, the  correlation  of  the  subject-matter  is,  nevertheless,  such  as  ensures 
logical  connection  in  treatment,  the  deductions  of  which  thoroughly  represent 
the  latest  advances  in  the  science,  and  which  elucidate  the  best  modern  methods 
of  procedure. 

The  more  conspicuous  feature  of  the  treatise  is  its  wealth  of  illustrative 
matter.  The  production  of  the  illustrations  had  been  in  progress  for  several 
years,  under  the  personal  supervision  of  Robert  L.  Dickinson,  M.  l)..t"  v 
artistic  judgment  and  professional  experience  is  due  the  most  sumptuously 
illustrated  work  of  the  period.  By  means  of  the  photographic  art,  combined 
with  the  skill  of  the  artist  and  draughtsman,  conventional  illustration  is  super- 
seded by  rational  methods  of  delineation. 

Furthermore,  the  volume  is  a  revelation  as  to  the  possibilities  that  may  be 
reached  in  mechanical  execution,  through   the   unsparing  hand  of  its  publisher. 


4  OVIKIKI  TOIt»: 


Dr.  James  C.  Cameron. 
Edward  P.  I >.i vis. 
Robert  L.  Dickinson. 
Charles  Warrington  Earle. 
James  H.  Etheridge. 
Henry  J.  Garrieues. 
Barton  Cooke  Hirst. 
Charles  Jewett, 


.  Howard  A.  Kelly. 
Richard  C.  N 
Chauncey  D.  Palmer. 
Theophilus  Parvin. 
George  A.  Piersol. 
I  rd  Reynolds. 

Henry  Schwarz. 


"  At  first  glance  we  are  overwhelmed  by  the  magnitude  of  this  work  in  several  respects, 
viz.  :  First,  by  the  size  of  the  volume,  then  by  the  array  of  eminent  teachers  in  this  depart- 
ment who  have  taken  part  in  it>  production,  then  by  the  profuseness  and  character  of  the 
illustrations,  and  last,  but  not  least,  the  conciseness  and  1  learness  with  which  the  text  is  ren- 
dered.    This  is  .m  entirely  new positi  m,  1  mbodj  ing  the  highest  knowledge  of  the  art  as 

it  stands  to-day  by  authors  who  occupy  the  front  rank  in  their  specialty,  and  dure  are  many 
of  them.  We  cannot  (urn  over  these  pages  without  being  struck  by  the  superb  illustrations 
which  adorn  so  many  of  them.      We  nfident  that  this  most  practical  work  will  find 

instant  appreciation  by  practitioners  as  well  as  students." — Neiv  York  Medical  Times. 

Permit  me  to  say  that  your  American  Ti  xt-B  i  'k  of  Obstetrics  is  the  most  magnificent 
medical  work  that  1  have  ever  seen.  I  congratulate  you  and  thank  you  for  this  superb  work. 
which  alone  is  sufficient  to  place  you  first  in  the  ranks  of  medical  publishers. 

With  profound  respect  I  am  sincerely  yours,  Ai  EX.  J.  C.  Skene. 


W.   B.   SAUNDERS' 


For  Sale  by  Subscription. 


AN  AMERICAN  TEXT-BOOK  ON  THE  THEORY  AND 
PRACTICE  OF  MEDICINE.  By  American  Teachers.  Edited 
by  William  Pepper,  M.  D.,  LL.D.,  Provost  and  Professor  of  the  Theory 
and  Practice  of  Medicine  and  of  Clinical  Medicine  in  the  University  of 
Pennsylvania.  Complete  in  two  handsome  royal-octavo  volumes  of  about 
iooo  pages  each,  with  illustrations  to  elucidate  the  text  wherever  necessary. 
Price  per  Volume  :  Cloth,  $5.00  net ;  Sheep  or  Half-Morocco,  #6.00  net. 


VOLUME   I.   CONTAINS; 


Hygiene. — Fevers  ( Ephemeral,  Simple  Con- 
tinued, Typhus,  Typhoid,  Epidemic  Cerebro- 
spinal Meningitis,  and  Relapsing) — -Scarla- 
tina, Measles,  Roth-eln,  Variola,  Varioloid, 
V  jccinia, Varicella,  Mumps, Whooping-cough, 
Anthrax,  Hydrophobia,  Trichinosis,  Actino- 


mycosis, Glanders,  and  Tetanus. — Tubercu- 
losis, Scrofula,  Syphilis,  Diphtheria,  Erysipe- 
las, Malaria,  Cholera,  and  Yellow  Fever. — 
Nervous,  Muscular,  and  Mental  Diseases  etc. 


VOLUME   II.  CONTAINS: 


Urine  (Chemistry  and  Microscopy). — Kid- 
ney and  Lungs. — Air-passages  (Larynx  and 
Bronchi)  and  Pleura. — Pharynx,  CEsophagus, 
Stomach  and  Intestines  (including  Intestinal 
Parasites),  Heart,  Aorta,  Arteries  and  Veins. 


—  Peritoneum,  Liver, and  Pancreas. — Diathet- 
ic Diseases  (Rheumatism,  Rheumatoid  Ar- 
thritis, Gout,  Lithaemia,  and  Diabetes.) — 
Blood  and  Spleen. — Inflammation,  Embolism, 
Thrombosis,  Fever,  and  Bacteriology. 


The  articles  are  not  written  as  though  addressed  to  students  in  lectures,  but 
are  exhaustive  descriptions  of  diseases,  with  the  newest  facts  as  regards  Causa- 
tion, Symptomatology,  Diagnosis,  Prognosis,  and  Treatment,  including  a  large 
number  of  approved  formulae.  The  recent  advances  made  in  the  study 
of  the  bacterial  origin  of  various  diseases  are  fully  described,  as  well  as  the 
bearing  of  the  knowledge  so  gained  upon  prevention  and  cure.  The  subjects 
of  Bacteriology  as  a  whole  and  of  Immunity  are  fully  considered  in  a  separate 
section. 

Methods  of  diagnosis  are  given  the  most  minute  and  careful  attention,  thus 
enabling  the  reader  to  learn  the  very  latest  methods  of  investigation  without 
consulting  works  specially  devoted  to  the  subject. 


CONTRIBUTORS : 


Dr.  J.  S.  Billings,  Philadelphia. 
Francis  Delafield,  New  York. 
Reginald  H.  Fitz,  Boston. 
James  W.  Holland,  Philadelphia. 
Henry  M.  Lyman,  Chicago. 
William  Osier,  Baltimore. 


Dr.  William  Pepper,  Philadelphia. 
W.  Gilman  Thompson,  New  York. 
W.  H.  Welch.  Baltimore. 
James  T.  Whittaker,  Cincinnati. 
James  C.  Wilson,  Philadelphia. 
Horatio  C.  Wood,  Philadelphia. 


"  We  reviewed  the  first  volume  of  this  work,  and  said  :  '  It  is  undoubtedly  one  of  the  best 
text-books  on  the  practice  of  medicine  which  we  possess.'  A  consideration  of  the  second 
and  last  volume  leads  us  to  modify  that  verdict  and  to  say  that  the  completed  work  ts,  in  our 
opinion,  the  best  of  its  kind  it  has  ever  been  our  fortune  to  see.  It  is  complete,  thorough, 
accurate,  and  clear.  It  is  well  written,  well  arranged,  well  printed,  well  illustrated,  and  well 
bound.    It  is  a  model  of  what  the  modern  text-book  should  be." — New  York  Medical  Journal. 

"A  library  upon  modern  medical  art.  The  work  must  promote  the  wider  diffusion  of 
sound   knowledge." — American  Lancet. 

"  A  trusty  counsellor  for  the  practitioner  or  senior  student,  on  which  he  may  implicitly 
rely." — Edinburgh  Medical  Journal. 


CATALOGUE    OF  MEDICAL    WORKS. 


For  Sale  by  Subscription. 


AN  AMERICAN  TEXT-BOOK   OF  SURGERY.      Edited  by  Wil- 
liam W.  Keen,  M.D.,  LL.D.,  and  J.  William  White,  M.  D.,  Ph.  D. 

Forming  one  handsome  royal-octavo  volume  of  1250  pages  (10x7  inches), 
with  500  wood-cuts  in  text,  and  37  colored  and  half-tone  plates,  many  of 
them  engraved  from  original  photographs  and  drawings  furnished  by  the 
authors.     Prices:  Cloth,  $7. 00  net;  Sheep  or  Half- Morocco,  38.00  net. 

SECOND  EDITION,  REVISED  AND  ENLARGED, 
With  a  Section  devoted  to  "The  Use  of  the  Rbntgen  Rays  in  Surgery." 

The  want  of  a  text-book  which  could  be  used  by  the  practitioner  and  at  the 
same  time  be  recommended  to  the  medical  student  has  been  deeply  felt,  espe- 
cially by  teachers  of  surgery;  hence,  when  it  was  suggested  to  a  nuni! 
these  that  it  would  be  well  to  unite  in  preparing  a  text-book  of  this  description, 
great  unanimity  of  opinion  was  found  to  exist,  and  the  gentlemen  below  named 
gladly  consented  to  join  in  its  production.  While  there  is  no  distinctive  Amer- 
ican Surgery,  yet  America  has  contributed  very  largely  to  the  progress  of  modern 
surgery,  and  among  the  foremost  of  those  who  have  aided  in  developing  this  art 
and  science  will  be  found  the  authors  of  the  present  volume.  All  of  tbem  are 
teachers  of  surgery  in  leading  medical  schools  and  hospitals  in  the  United  States 
and  Canada. 

Especial  prominence  has  been  given  to  Surgical  Bacteriology,  a  feature  which 
is  believed  to  be  unique  in  a  surgical  text-book  in  the  English  language.  Asep- 
sis and  Antisepsis  have  received  particular  attention.  The  text  is  brought  well 
up  to  date  in  such  important  branches  as  cerebral,  spinal,  intestinal,  and  pelvic 
surgery,  the  most  important  and  newest  operations  in  these  departments  being 
described  and  illustrated. 

The  text  of  the  entire  book  has  been  submitted  to  all  the  authors  for  their 
mutual  criticism  and  revision — an  idea  in  book-making  that  is  entirely  new  and 
original.  The  book  as  a  whole,  therefore,  expresses  on  all  the  important  sur- 
gical topics  of  the  day  the  consensus  of  opinion  of  the  eminent  surgeons  who 
have  joined  in  its  preparation. 

One  of  the  most  attractive  features  of  the  book  is  its  illustrations.  Very 
many  of  them  are  original  and  faithful  reproductions  of  photographs  taken 
directly  from  patients  or  from  specimens. 

CONTRIBUTORS: 


Dr.  Charles  H    Burnett,  Philadelphia. 
Phineas  S.  Conner,  Cincinnati. 
Frederic  S.  Dennis,  New  York. 
William  VV.  Keen,  Philadelphia 
Charles  B  Nancrede,  Ann  Arbor,  Mich. 
Roswell  Park,  Buffalo,  N.  Y. 
Lewis  S.  Pilcher,  New  York. 


Dr.  Nicholas  Senn,  Chicago. 

Francis  J.  Shepherd.  Montreal,  Canada. 
Lewis  A.  Stimson,  New  York. 
William  Thomson,  Philadelphia. 
'  J.  Collins  Warren,  Boston, 
j.  William  White,  Philadelphia. 


"  If  this  text-book  is  a  fair  reflex  of  ihc  present  position  of  American  surgery,  we  must 
admit  it  is  of  a  very  high  order  of  merit,  and  that  English  surgeons  will  have  to  look  very 
carefully  to  their  laurels  if  they  are  to  preserve  a  position  in  the  van  of  surgical  practice." — 
London  Lancet. 


W.   B.   SAUNDERS' 


For  Sale  by  Subscription. 


AN  AMERICAN  TEXT-BOOK  OF  GYNECOLOGY,  MEDICAL 
AND  SURGICAL,  for  the  use  of  Students  and  Practitioners. 
Edited  by  J.  M.  Baldy,  M.  D.  Forming  a  handsome  royal-octavo  volume, 
with  360  illustrations  in  text  and  37  colored  and  half-tone  plates.  Prices: 
Cloth,  #6.00  net;  Sheep  or  Half-Morocco,  #7.00  net. 

In  this  volume  all  anatomical  descriptions,  excepting  those  essential  to  a  clear 
understanding  of  the  text,  have  been  omitted,  the  illustrations  being  largely  de- 
pended upon  to  elucidate  the  anatomy  of  the  parts.  This  work,  which  is 
thoroughly  practical  in  its  teachings,  is  intended,  as  its  title  implies,  to  be  a 
working  text-book  for  physicians  and  students.  A  clear  line  of  treatment  has 
been  laid  down  in  every  case,  and  although  no  attempt  has  been  made  to  dis- 
cuss mooted  points,  still  the  most  important  of  these  have  been  noted  and  ex- 
plained. The  operations  recommended  are  fully  illustrated,  so  that  the  reader, 
having  a  picture  of  the  procedure  described  in  the  text  under  his  eye,  cannot  fail 
to  grasp  the  idea.  All  extraneous  matter  and  discussions  have  been  carefully 
excluded,  the  attempt  being  made  to  allow  no  unnecessary  details  to  cumber 
the  text.  The  subject-matter  is  brought  up  to  date  at  every  point,  and  the 
work  is  as  nearly  as  possible  the  combined  opinions  of  the  ten  specialists  who 
figure  as  the  authors. 

The  work  is  well  illustrated  throughout  with  wood-cuts,  half-tone  and 
colored  plates,  mostly  selected  from  the  authors'  private  collections. 


CONTRIBUTORS : 


Dr.  Henry  T.  Byford. 
John  M.  Baldy. 
Edwin  Cragin. 
».  H.  Etheridge. 
William  Goodell. 


Dr.  Howard  A.  Kelly. 
Florian  Krug. 
E.  E.  Montgomery. 
William  R.  Pryor. 
George  M.  Tuttle. 


"The  most  notable  contribution  to  gynecological  literature  since  1887 and  the  most 

complete  exponent  of  gynecology  which  we  have.  No  subject  seems  to  have  been  neglected, 
....  and  the  gynecologist  and  surgeon,  and  the  general  practitioner  who  has  any  desire 
to  practise  diseases  of  women,  will  find  it  of  practical  value.  In  the  matter  of  illustrations 
and  plates  the  book  surpasses  anything  we  have  seen." — Boston  Medical  and  Surgical 
"Journal. 

"A  valuable   addition   to  the  literature  of  Gynecology.      The  writers   are   progressive, 
aggressive,  and  earnest  in  their  convictions." — Medical  News,  Philadelphia. 

"  A  thoroughly  modern  text-book,  and  gives  reliable  and  well-tempered  advice  and  in- 
struction."— Edinburgh  Medical  Journal. 

"  The  harmony  of  its  conclusions  and  the  homogeneity  of  its  style  give  it  an  individuality 
which  suggests  a  single  rather  than  a  multiple  authorship." — Annals  of  Surgery. 

"  It  must  command  attention  and  respect  as  a  worthy  representation  of  our  advanced 
clinical  teaching." — American  Journal  oj  Medical  Sciences. 


CATALOGUE    OF  MEDICAL    WORKS. 


For  Sale  by  Subscription. 


AN  AMERICAN  TEXT-BOOK  OF  THE  DISEASES  OF  CHIL- 
DREN. By  American  Teachers.  Edited  by  Louis  Stark,  M.  1)., 
assisted  by  THOMPSON  S.  Westcott,  M.  D.  In  one  handsome  royal-8va 
volume  of  1190  pages,  profusely  illustrated  with  wood  cuts,  half-tone  and 
colored  plates.    Net  Prices:  Cloth, $7.00;  Sheep  or  Half-Morocco,  % 

The  plan  of  this  work  embraces  a  series  of  original  articles  written  by  some 
sixty  well-known  psediatrists,  representing  collectively  the  teachings  of  tin 
prominent  medical  schools  and  colleges  of  America.     The  work  is  intended  to 
be  a  practical  book,  suitable  for  constant  and  handy  reference  by  the  practi- 
tioner and  the  advanced  student. 

One  decided  innovation  is  the  large  number  of  authors,  nearly  every  article 
being  contributed  by  a  specialist  in  the  linj  on  which  he  writes.  This,  while 
entailing  considerable  labor  upon  the  editors,  has  resulted  in  the  publication  of 
a  work  THOROUGHLY    NEW    AND    ABREAST   OF  THIi  TIMES. 

Especial  attention  has  been  given  to  the  latest  accepted  teachings  upon  the 
etiology,  symptoms,  pathology,  diagnosis,  and  treatment  of  the  disorders  of  chil- 
dren, with  the  introduction  of  many  special  formulae  and  therapeutic  procedures. 

Special  chapters  embrace  at  unusual  length  the  Diseases  of  the  Eye,  Ear, 
Nose  and  Throat,  and  the  Skin  ;  while  the  introductory  chapters  cover  fully  the 
important  subjects  of  Diet,  Hygiene,  Exercise,  Bathing,  and  the  Chemistry  of 
Food.  Tracheotomy,  Intubation,  Circumcision,  and  such  minor  surgical  pro- 
cedures coming  within  the  province  of  the  medical  practitioner  are  carefully 
considered. 

CONTRIBUTORS : 

Dr.  Thomas  S.  Latimer,  Baltimore. 


Dr.  S.  S.  Adams,  Washington. 

John  Ashhurst,  Jr.,  Philadelphia. 
A.  U.  Blackader,  Montreal,  Canada. 
Dillon  Brown,  New  York. 
Edward  M.  Buckingham,  Boston. 
Charles  W.  Burr,  Philadelphia. 
W.  E.  Casselberry,  Chicago. 
Henry  Dwight  Chapin,  New  York. 
W.  S.  Christopher,  Chicago. 
Archibald  Church,  Chicago 
Floyd  M.  Crandall,  New  York. 
Andrew  F.  Currier,  New  York. 
Roland  G.  Curtin,  Philadelphia 
J.  M.  DaCosta,  Philadelphia. 
I.  N.  Danforth,  Chicago. 
Edward  P.  Davis,  Philadelphia. 
John  B.  Deaver,  Philadelphia. 
G.  E.  de  Schweinitz,  Philadelphia. 
John  Doming,  New  York. 
Charles  Warrington  Farle,  Chi 
W'm.  A.  Edwards,  San  Diego,  Cal. 
F.  Forchheimer,  Cincinnati. 

J.  Henry  Fruitnight,  New  York. 
Landon  Carter  Gray,  New  York. 
J.  P.  Crozer  Griffith,  Philadelphia. 
\\  .  A.  Hardaway.  St.  Louis. 
M.  P   Hatfield,  Chicago. 
Barton  Cooke  Hirst,  Philadelphia. 
H.  Illoway,  Cincinnati. 
Henry  Jackson,  Boston. 
Charles  G.  Jennings,  Detroit. 
Henry  Koplik.  New  York. 


Albert  R.  Leeds,  Hoboken,  N.  J. 
J.  Hendrie  Lloyd,  Philadelphia. 
George  Roe  Lockwood,  New  York. 
Henry  M.  Lyman,  Chicago. 
Francis  T.  Miles,  Baltimore. 
Charles  K    Mills,  Philadelphia. 
John  H.  Musser,  Philadelphia. 
'Thomas  R.  Neilson,  Philadelphia. 
W.  P.  Northrop,  New  York. 
William  Osier,  Baltimore. 
Frederick  A    Packard,  Philadelphia. 
William  Pepper,  Philadelphia. 
Frederick  Peterson,  New  York. 
W.    1 .  Plant,  Syracuse,  New  York. 
William  M.  Powell,  Atlantic  City. 
B.  Alexander  Randall,  Philadelphia. 
Edward  O.  Shakespeare,  Philadelphia 

F.  C.  Shattuck,  Boston, 

J.  Lewis  Smith,  New  York. 

LouU  Starr,  Philadelphia. 

M.  Allen  Starr,  New  York. 

J.  Madison  Taylor,  Philadelphia. 

Charles  YV .  Townsi  nd,  Boston, 

James  Tyson,  Philadelphia. 

W.  S.  Thayer,  Baltimore. 

Victor  C.  Vaughan,  Ann  Arbor.  Mich 

Thompson  S.  Westcott,  Philadelphia. 

Henry  R.  Wharton,  Philadelphia. 

J.  Willi. on  White.  Philadelphia. 

J- 


C.  Wilson,  Philadelphia. 


10  iv.   B.   SAUNDERS' 


A  NEW  PRONOUNCING  DICTIONARY  OF  MEDICINE,  with 
Phonetic  Pronunciation,  Accentuation,  Etymology,  etc.  By  John 
M.  Keating,  M.  D.,  LL.D.,  Fellow  of  the  College  of  Physicians  of  Phila- 
delphia; Vice-President  of  the  American  Pediatric  Society;  Ex-President 
of  the  Association  of  Life  Insurance  Medical  Directors;  Editor  "  Cyclo- 
paedia of  the  Diseases  of  Children,"  etc.;  and  Henry  Hamilton,  author 
of  "  A  New  Translation  of  Virgil's  ^Eneid  into  English  Rhyme ;"  co- 
author of  "  Saunders'  Medical  Lexicon,"  etc. ;  with  the  Collaboration  of 
J.  Chalmers  DaCosta,  M.  D.,  and  Frederick  A.  Packard,  M.  D. 
With  an  Appendix  containing  important  Tables  of  Bacilli,  Micrococci, 
Leucoma'ines,  Ptomaines,  Drugs  and  Materials  used  in  Antiseptic  Sur- 
gery, Poisons  and  their  Antidotes,  Weights  and  Measures,  Thermometric 
Scales,  New  Official  and  Unofficial  Drugs,  etc.  One  very  attractive  volume 
of  over  800  pages.  Second  Revised  Edition.  Prices:  Cloth,  $5.00  net-; 
Sheep  or  Half- Morocco,  $6.00  net;  with  Denison's  Patent  Ready- Refer- 
ence Index ;  without  patent  index,  Cloth,  $4.00  net ;  Sheep  or  Half- 
Morocco,  $5.00  net. 

PROFESSIONAL,   OPINIONS. 

"  I  am  much  pleased  with  Keating's  Dictionary,  and  shall  take  pleasure  in  recommending 
it  to  my  classes." 

Henkv  M.  Lyman,  M.  D., 
Professor  of  Principles  and  Practice  of  Medicine,  Rush  Medical  College,  Chicago,  III. 

"  I  am  convinced  that  it  will  be  a  very  valuable  adjunct  to  my  study-table,  convenient  in 
size  and  sufficiently  full  for  ordinary  use." 

C.  A.  Linusley,  M.  D., 
Professor  of  Theory  and  Practice  of  Medicine,  Medical  Dept.  Yale  University ; 

Secretary  Connecticut  State  Board  of  Health,  New  Haven,  Conn, 


AUTOBIOGRAPHY  OF  SAMUEL  D.  GROSS,  M.  D.,  Emeritus  Pro- 
fessor of  Surgery  in  the  Jefferson  Medical  College  of  Philadelphia,  with 
Reminiscences  of  His  Times  and  Contemporaries.      Edited  by  his  sons, 
Samuel  W.  Gross,  M.  D.,  LL.D.,  late  Professor  of  Principles  of  Surgery 
and  of  Clinical  Surgery  in  the  Jefferson  Medical  College,  and  A.  Hali.er 
Gross,  A.  M.,  of  the  Philadelphia  Bar.     Preceded  by  a  Memoir  of  Dr. 
Gross,  by  the  late  Austin  Flint,  M.  D.,  LL.D.     In  two  handsome  volumes, 
each  containing  over  400  pages,  demy  8vo,  extra  cloth,  gilt  tops,  with  fine 
Frontispiece  engraved  on  steel.     Price  per  Volume,  $2.50  net. 
This  autobiography,  which  was  continued  by  the  late  eminent  surgeon  until 
within  three   months  of  his  death,  contains  a   full   and  accurate  history  of  his 
early  struggles,  trials,  and  subsequent  successes,  told  in  a  singularly  interesting 
and  charming  manner,  and  embraces  short  and  graphic  pen-portraits  of  many 
of  the  most  distinguished  men — surgeons,  physicians,  divines,  lawyers,  states- 
men, scientists,  etc. — with  whom  he  was  brought  in  contact  in  America  and  in 
Europe ;  the  whole  forming  a  retrospect  of  more  than  three-quarters  of  a  century. 


CATALOGUE    OF  MEDICAL    WORKS.  II 


SURGICAL  PATHOLOGY  AND  THERAPEUTICS.  By  John 
Collins  Warren,  M.  D.,  LL.D.,  Professor  of  Surgery,  Medical  Depart- 
ment Harvard  University;  Surgeon  to  the  Massachusetts  General  Hospital, 

etc.  A  handsome  octavo  volume  of  832  pa^es,  with  136  relief  and  litho- 
graphic illustrations,  ^  of  which  are  printed  in  colors,  and  all  of  which 
were  drawn  by  William  J.  Kaula  from  original  specimens.  Prices:  Cloth, 
$6.00  net;    Half-Morocco,  $7.00  net. 

"  The  volume  is  for  the  bedside,  the  amphitheatre,  and  the  ward.  It  deals 
with  things  not  as  we  see  them  through  the  microscope  alone,  but  as  the  prac- 
titioner sees  their  effect  in  his  patients ;  not  only  as  they  appear  in  and  affect 
culture-media,  hut  also  as  they  influence  the  human  body;  and,  following  up 
the  demonstrations  of  the  nature  of  diseases,  the  author  points  out  their  logical 
treatment."  [New  York  Medical  Journal).  "  It  is  the  handsomest  spe< 
of  hook-making  *  *  *  that  has  ever  been  issued  from  the  American  medical 
press "    {American   Journal  of  the  Medical  Sciences,   Philadelphia). 

Without  Exception,  the  Illustrations   are   the   Best  ever  Seen  in  a 
Work  of  this  Kind. 

"A  most  striking  and  very  excellent  feature  of  this  book  is  its  illustrations.  Without  ex- 
ception, from  the  point  of  accuracy  and  artistic  merit,  they  are  the  best  ever  seen  in  a  work 
of  this  kind.  *  *  *  Many  of  those  representing  microscopic  pictures  are  so  perfect  in  their 
coloring  and  detail  as  almost  to  give  the  beholder  the  impression  that  lie  is  looking  down  the 
barrel  of  a  microscope  at  a  well-mounted  section.  " — Annals  of  Surgery,  Philadelphia. 

PATHOLOGY  AND  SURGICAL  TREATMENT  OF  TUMORS. 
By  N.  Senn,  M.  D.,  Ph.  D.,  LL.  D.,  Professor  of  Practice  of  Surgery  and 
of  Clinical  Surgery,  Rush  Medical  College;  Professor  of  Surgery,  <  hicago 
Polyclinic;  Attending  Surgeon  to  Presbyterian  Hospital;  Surgeon-in-Chief, 
St.  Joseph's  Hospital,  Chicago.  One  volume  of  710  pages,  with  515 
engravings,  including  full-page  colored  plates.  Prices:  Cloth,  36.00  net; 
Half-Morocco,  $7.00  net. 

Books  specially  devoted   to  this  subject  are  few,  and   in  our  text-books  and 

systems  of  surgery  this  part  of  surgical  pathology  is  usually  condensed  to  a  de- 
gree incompatible  with  its  scientific  and  clinical  importance.  The  author  spent 
many  years  in  collecting  the  material  for  this  work,  and  has  taken  great  pains 
to  present  it  in  a  manner  that  should  prove  useful  as  a  text-book  for  the  .student, 
a  work  of  reference  for  the  busy  practitioner,  and  a  reliable,  safe  guide  for  the 
surgeon.  The  more  difficult  operations  are  fully  described  and  illustrated.  More 
than  one  hundred  of  the  illustrations  are  original,  while  the  remainder  were 
selected  from  books  and  medical   journals   not  readily  accessible. 

"  The  most  exhaustive  of  any  recent  book  in  English  on  this  subject.  It  is  well  illus- 
trated, and  will  doubtless  remain  as  the  principal  monograph  on   the  subject  in  our  language 

for  some  years.     The  book  is  handsomely  illustrated  and  printed and  the  author  has 

given  a  notable  and  lasting  contribution  to  Mirgery." — Journal  of  American  Medical  Asso- 
ciation, Chicago. 


12  W.  B.    SAUNDERS' 


MEDICAL  DIAGNOSIS.  By  Dr.  Oswald  Vierordt,  Professor  of 
Medicine  at  the  University  of  Heidelberg.  Translated,  with  additions, 
from  the  Second  Enlarged  German  Edition,  with  the  author's  permission, 
by  Francis  H.  Stuart,  A.  M.,  M.  D.  Third  and  Revised  Edition.  In 
one  handsome  royal-octavo  volume  of  700  pages,  178  fine  wood-cuts  in 
text,  many  of  which  are  in  colors.  Prices:  Cloth,  $4.00  net;  Sheep  or 
Half-Morocco,  $5.00   net. 

In  this  work,  as  in  no  other  hitherto  published,  are  given  full  and  accurate 
explanations  of  the  phenomena  observed  at  the  bedside.  It  is  distinctly  a  clin- 
ical work  by  a  master  teacher,  characterized  by  thoroughness,  fulness,  and  accu- 
racy. It  is  a  mine  of  information  upon  the  points  that  are  so  often  passed  over 
without  explanation.  Especial  attention  has  been  given  to  the  germ-theory  as  a 
factor  in  the  origin  of  disease. 

This  valuable  work  is  now  published  in  German,  English,  Russian,  and 
Italian.  The  issue  of  a  third  American  edition  within  two  years  indicates  the 
favor  with  which  it  has  been  received  by  the  profession. 

THE  PICTORIAL  ATLAS  OF  SKIN  DISEASES  AND  SYPHI- 
LITIC AFFECTIONS.  (American  Edition.)  Translation  from 
the  French.  Edited  by  J.  J.  Pringi.K,  M.  B.,  F.  R.  C.  P.,  Assistant  Phy- 
sician to,  and  Physician  to  the  department  for"  Diseases  of  the  Skin  at,  the 
Middlesex  Hospital,  London.  Photo-lithochromes  from  the  famous  models 
of  dermatological  and  syphilitic  cases  in  the  Museum  of  the  Saint-Louis 
Hospital,  Paris,  with  explanatory  wood-cuts  and  letter-press.  In  12  Parts, 
at  $3.00  per  Part.     Parts  1  to  8  now  ready. 

"The  plates  are  beautifully  executed." — Jonathan  Hutchinson,  M.  D.  (London 
Hospital). 

"  The  plates  in  this  Atlas  are  remarkably  accurate  and  artistic  reproductions  of  typical 
examples  of  skin  disease.  The  work  will  be  of  great  value  to  the  practitioner  and  student." 
— William  Anderson,  M.  D.  (St.  Thomas  Hospital). 

"  If  the  succeeding  parts  of  this  Atlas  are  to  be  similar  to  Part  1,  now  before  us,  we  have 
no  hesitation  in  cordially  recommending  it  to  the  favorable  notice  of  our  readers  as  one  of 
the  finest  dermatological  atlases  with  which  we  are  acquainted." — Glasgow  Medical  "Journal, 
Aug.,  1895. 

"  Of  all  the  atlases  of  skin  diseases  which  have  been  published  in  recent  years,  the  present 
one  promises  to  be  of  greatest  interest  and  value,  especially  from  the  standpoint  of  the 
general  practitioner." — American  Medico-Surgical  Bulletin,  Feb.  22,  1896. 

"The  introduction  of  explanatory  wood-cuts  in  the  text  is  a  novel  and  most  important 
feature  which  greatly  furthers  the  easier  understanding  of  the  excellent  plates,  than  which 
nothing,  we  venture  to  say,  has  been  seen  better  in  point  of  correctness,  beauty,  and  general 
merit." — New  York  Medical  Journal ,  Feb.  15,  1896. 

"  An  interesting  feature  of  the  Atlas  is  the  descriptive  text,  which  is  written  for  each  picture 
by  the  physician  who  treated  the  case  or  at  whose  instigation  the  models  have  been  made. 
We  predict  for  this  truly  beautiful  work  a  large  circulation  in  all  parts  of  the  medical  world 
where  the  names  St.  Louis  and  Baretta  have  preceded  it." — Medical  Record,  N.  Y.,  Feb.  1, 


CATALOGUE    OF  MEDICAL    WORKS.  1 3 

PRACTICAL    POINTS    IN     NURSING.     For    Nurses    in    Private 
Practice.     By  Emily   A.   M.   Stoney,  Graduate  of  the  Training 
for  Nurses,  Lawrence,  Mass.;  Superintendent  of  the  Training-School  for 
Nurses,  I  arnej   Hospital,  South  Boston,   Mass.     456  pages,  ham 
illustrated  with  73  engravings  in  the   text,  and  9  colored  and  half-tone 
plates.     Cloth.     Price,  51.75  net 

SECOND  EDITION,  THOROUGHLY  REVISED. 

In   this  volume   the  author  explains,  in   popular  language  and  in  the  si 
possible  form,  the  entire  ranoe  of  private  nursing  as  distinguished  from  hospital 
nursing,  and  the  nurse  is  instructed  how  best  to  meet  the  various  em  1 
medical  and  surgical  cases  when  distant  from  medical  or  surgical  aid  or  when 
thrown  on  her  own  resources. 

An  especially  valuable  feature  of  the  work  will  be  found  in  the  directions  to 
the  nurse  how  to  improvise  everything  ordinarily  needed  in  the  sick-room,  where 
the  embarrassment  of  the  nurse,  owing  to  the  want  of  proper  appliances,  is  fre- 
quently extreme. 

The  work  has  been  logically  divided  into  the  following  sections: 

I.  The  Nurse:  her  responsibilities,  qualifications,  equipment,  etc. 
II.   The  Sick- Room:   its  selection,  preparation,  and  management. 

III.  The  Patient :  duties  of  the  nurse  in  medical,  surgical,  obstetric,  and  gyne- 

cologic cases. 

IV.  Nursing  in  Accidents  and  Emergencies. 
V.   Nursing  in  Special  Medical  Cases. 

VI.   Nursing  of  the  New-born  and  Sick  Children. 
VII.  Physiology  and  Descriptive  Anatomy. 

The  Appendix  contains  much  information  in  compact  form  that  will  be  found 
of  great  value  to  the  nurse,  including  Rules  for  Feeding  the  Sick;   Reci] 
Invalid   Foods  and   Beverages;    fables  of  Weights  and    Measures;    Table  for 
Computing  the   Date  of  Labor;   List  of  Abbreviations ;  Dose-List;  and  a  full 
and  complete  Glossary  of  Medical  Terms  and  Nursing  Treatment. 

"This  is  a  well  written,  eminently  practical  volume,  which  covers  the  entire  range  of 
private  nursing  as  distinguished  from  hospital  nursing,  and  instructs  the  nurse  how  hest  to 
meet  the  various  emergencies  which  may  .'.rise  and  how  to  prepare  everything  ordinarily- 
needed  in  the  illness  of  her  patient." — American  Journal  of  Obstetrics  and  Diseases  of 
W  men  and  Children,  Aug.,  1896. 

A    TEXT-BOOK   OF    BACTERIOLOGY,   including   the    Etiology  and 

Prevention  of  Infective  Diseases  and  an  account  of  Yeasts  and  Moulds, 
Hiematozoa,  a;  rms.     by  EDGAR  M.  CrookSHANK,  M.  B., 

fessor  of  Comparative  Pathology  and  Bacteriology,  Kino-  College,  bond. .11. 
A  handsome  octavo  volume  of  700  pages,  with  273  engravings  in  the  text, 
and  22  original  and  colored  plates.      Price,  S6.50  net. 

This  book,  though  nominally  a   Fourth   Edition  of    Professor  Crookshank's 

"  Manual  <>i    Bacteriology,"  1-  practically  a  new  work,  the  old  one  having 
been  reconstructed,  greatly  enlarged,  revised  throughout,  and   largely  rewritten, 
forming  a  text-book  for  the  Bacteriological  Lalxjratory,  for  Medical  <  'tn 
Health,  and  for  Veterinary  Inspectors. 


14  IV.   B.   SAUNDERS1 


A  TEXT-BOOK  OF  HISTOLOGY,  DESCRIPTIVE  AND  PRAC- 
TICAL. For  the  Use  of  Students.  By  Arthur  Clarkson,  M.  B., 
C.  M.,  Edin.,  formerly  Demonstrator  of  Physiology  in  the  Owen's  College, 
Manchester;  late  Demonstrator  of  Physiology  in  the  Yorkshire  College, 
Leeds.  Large  8vo,  554  pages,  with  22  engravings  in  the  text,  and  174 
beautifully  colored  original  illustrations.  Price,  strongly  bound  in  Cloth, 
$6.00  net. 

The  purpose  of  the  writer  in  this  work  has  been  to  furnish  the  student  of  His- 
tology, in  one  volume,  with  both  the  descriptive  and  the  practical  part  of  the 
science.  The  first  two  chapters  are  devoted  to  the  consideration  of  the  general 
methods  of  Histology ;  subsequently,  in  each  chapter,  the  structure  of  the  tissue 
or  organ  is  first  systematically  described,  the  student  is  then  taken  tutorially  over 
the  specimens  illustrating  it,  and,  finally,  an  appendix  affords  a  short  note  of  the 
methods  of  preparation. 

"We  would  most  cordially  recommend  it  to  all  students  of  histology." — Dublin  Medical 
Journal. 

"  It  is  pleasant  to  give  unqualified  praise  to  the  colored  illustrations  ;  .  .  .  the  standard  is 
high,  and  many  of  them  are  not  only  extremely  beautiful,  but  very  clear  and  demonstra- 
tive. .  .  .  The  plan  of  the  book  is  excellent." — Liverpool  Medical  Journal. 

ARCHIVES  OF  CLINICAL  SKIAGRAPHY.  By  Sydney  Rowland, 
B.  A.,  Camb.  A  series  of  collotype  illustrations,  with  descriptive  text, 
illustrating  the  applications  of  the  New  Photography  to  Medicine  and  Sur- 
gery.    Price,  per  Part,  $1.00.      Parts  I.  to  V.  now  ready. 

The  object  of  this  publication  is  to  put  on  record  in  permanent  form  some  of 
the  most  striking  applications  of  the  new  photography  to  the  needs  of  Medicine 
and  Surgery. 

The  progress  of  this  new  art  has  been  so  rapid  that,  although  Prof.  Rontgen's 
discovery  is  only  a  thing  of  yesterday,  it  has  already  taken  its  place  among  the 
approved  and  accepted  aids  to  diagnosis. 

WATER  AND  WATER  SUPPLIES.  By  John  C.  Thresh,  D.  Sc, 
M.  B.,  D.  P.  H,  Lecturer  on  Public  Health,  King's  College,  London ; 
Editor  of  the  "Journal  of  State  Medicine,"  etc.  i2mo,  438  pages,  illus- 
trated. Handsomely  bound  in  Cloth,  with  gold  side  and  back  stamps. 
Price,  $2.25  net. 

This  work  will  furnish  any  one  interested  in  public  health  the  information 
requisite  for  forming  an  opinion  as  to  whether  any  supply  or  proposed  supply 
is  sufficiently  wholesome  and  abundant,  and  whether  the  cost  can  be  considered 
reasonable. 

The  work  does  not  pretend  to  be  a  treatise  on  Engineering,  yet  it  contains 
sufficient  detail  to  enable  any  one  who  has  studied  it  to  consider  intelligently  any 
scheme  which  may  be  submitted  for  supplying  a  community  with  water. 


CATALOGUE    OF  MEDICAL    WORKS.  15 


DISEASES    OF    THE  EYE.     A  Hand-Book  of  Ophthalmic  Prac- 
tice.    By  (..  I-:,  de  Schweinitz,  M.  I).,  Professor  ol  Ophthalmology  in 

the  Jefferson  Medical  College,  Philadelphia,  etc.  A  handsome  royal- 
octavo  volume  of  679  pages,  with  256  fine  illustrations,  many  of  which  arc- 
original,  and  2  chromo-lithographic  plates.  Prices:  Cloth,  54.00  net; 
Sheep  or  Half- Morocco,  $5.00  net. 

The  object  of  this  work  is  to  present  to  the  student,  and  to  the  practitioner 
who  is  beginning  work  in  the  fields  of  ophthalmology,  a  plain  description  of  the 
optical  defects  and  diseases  of  the  eye.  To  this  end  special  attention  has  been 
paid  to  the  clinical  side  of  the  question  ;  and  the  method  of  examination,  the 
symptomatology  leading  to  a  diagnosis,  and  the  treatment  of  the  various  ocular 
defects  have  been  brought  into  prominence. 

SECOND   EDITION,   REVISED  AND  CREATLY   ENLARCED. 

The  entire  book  has  been  thoroughly  revised.  In  addition  to  this  general 
revision,  special  paragraphs  on  the  following  new  matter  have  been  introduced  : 
Filamentous  Keratitis,  Blood-staining  of  the  Cornea,  Essential  Phthisis  Bulbi, 
Foreign  Bodies  in  the  Lens,  Circinate  Retinitis,  Symmetrical  Changes  at  the 
Macula  Lutea  in  Infancy,  Hyaline  Bodies  in  the  Papilla,  Monocular  Diplopia, 
Subconjunctival  Injections  of  Germicides,  Infiltration-Anaesthesia,  and  Steriliza- 
tion of  Collyria.  Brief  mention  of  Ophthalmia  Nodosa,  Electric  Ophthalmia, 
and  Angioid  Streaks  in  the  Retina  also  finds  place.  An  Appendix  has  been 
added,  containing  a  full  description  of  the  method  of  determining  the  corneal 
astigmatism  with  the  ophthalmometer  of  Javal  and  Schiotz,  and  the  rotations 
of  the  eyes  with  the  tropometer  of  Stevens.  The  chapter  on  Operations  has 
been  enlarged  and  rewritten. 

"  A  clearly  written,  comprehensive  manual.  .  .  .  One  which  we  can  commend  to  students 
as  a  reliable  text-book,  written  with  an  evident  knowledge  of  the  wants  of  those  entering  upon 
the  study  of  this  special  branch  of  medical  science." —  Britis h  Medical  Journal. 

"  The  work  is  characterized  by  a  lucidity  of  expression  which  leaves  the  reader  in  no 
doubt  as  to  the  meaning  of  the  language  employed  .  .  .  We  know  of  no  work  in  which 
these  diseases  are  dealt  with  more  satisfactorily,  and  indications  for  treatment  more  clearly 
given,  and  in  harmony  with  the  practice  of  the  most  advanced  ophthalmologists." — Mari- 
time Medical 

"  It  is  hardly  too  much  to  say  that  for  the  student  and  practitioner  beginning  the  study  of 
Ophthalmology,  it  is  the  best  single  volume  at  present  published." — Medical  a 

"  The  latest  and  one  of  the  best  books  on  Ophthalmology.  The  book  is  thoroughly  up  to 
date,  and  is  certainly  a  work  which  not  only  commends  itself  to  the  student,  but  is  a  ready 
reference  for  the  busy  practitioner." — International  Medical  Review. 

PROFESSIONAL  OPINIONS. 

"A  work  that  will  meet  the  requirements  not  only  of  the  specialist,  but  of  the  general 
practitioner  in  a  rare  degree.     I  am  satisfied  that  unusual  success  awaits  it." 

W'111  i.\M  Pbppbr,  M.  I>. 
Provost  and  Professor  of  Theory  and  Practice  of  Medicine  and  Clinical  Medicine 
in  the  University  of  Pennsylvania. 

"  Contains  in  concise  and  reliable  form  the  accepted  views  of  Ophthalmic  Science." 

William  THOMSON,  M.  D., 
Professor  of  Ophthalmology,  Jefferson  Medical  College,  Philadelphia,  P*. 


1 6  IV.   B.   SAUNDERS" 


TEXT-BOOK  UPON  THE  PATHOGENIC  BACTERIA.  Spe- 
cially written  for  Students  of  Medicine.  By  Joseph  McFarland, 
M.  D.,  Professor  of  Pathology  and  Bacteriology  in  the  Medico-Chirurgical 
College  of  Philadelphia,  etc.  359  pages,  finely  illustrated.  Price,  Cloth, 
$2.50  net. 

The  book  presents  a  concise  account  of  the  technical  procedures  necessary  in 
the  study  of  Bacteriology.  It  describes  the  life-history  of  pathogenic  bacteria,  and 
the  pathological  lesions  following  invasion. 

The  work  is  intended  to  be  a  text-book  for  the  medical  student  and  for  the 
practitioner  who  has  had  no  recent  laboratory  training  in  this  department  of  medi- 
cal science.  The  instructions  given  as  to  needed  apparatus,  cultures,  stainings, 
microscopic  examinations,  etc.,  are  ample  for  the  student's  needs,  and  will  afford 
to  the  physician  much  information  that  will  interest  and  profit  him  relative  to  a 
subject  which  modern  science  shows  to  go  far  in  explaining  the  etiology  of  many 
diseased  conditions. 

The  illustrations  have  been  gathered  from  standard  sources,  and  comprise  the 
best  and  most  complete  aggregation  extant. 

"  It  is  excellently  adapted  for  the  medical  students  and  practitioners  for  whom  it  is  avowedly 
written.  .  .  .  The  descriptions  given  are  accurate  and  readable,  and  the  book  should  prove 
useful  to  those  for  whom  it  is  written. — London  Lancet,  Aug.  29,  1896. 

"  The  author  has  succeded  admirably  in  presenting  the  essential  details  of  bacteriological 
technics,  together  with  a  judiciously  chosen  summary  of  our  present  knowledge  of  pathogenic 
bacteria.  .  .  .  The  work,  we  think,  should  have  a  wide  circulation  among  English-speaking 
students  of  medicine." — N.  Y.  Medical  Journal,  April  4,  1896. 

"  The  book  will  be  found  of  considerable  use  by  medical  men  who  have  not  had  a  special 
bacteriological  training,  and  who  desire  to  understand  this  important  branch  of  medical 
science." — Edinburgh  Medical  Journal ,  July,  1896. 

LABORATORY    GUIDE    FOR    THE    BACTERIOLOGIST.      By 

Langdon  Frothingham,  M.  D.  V.,  Assistant  in  Bacteriology  and  Veteri- 
nary Science,  Sheffield  Scientific  School,  Yale  University.  Illustrated. 
Price,  Cloth,  75  cents. 

The  technical  methods  involved  in  bacteria-culture,  methods  of  staining,  and 
microscopical  study  are  fully  described  and  arranged  as  simply  and  concisely  as 
possible.     The  book  is  especially  intended  for  use  in  laboratory  work 

"  It  is  a  convenient  and  useful  little  work,  and  will  more  than  repay  the  outlay  necessary 
for  its  purchase  in  the  saving  of  time  which  would  otherwise  be  consumed  in  looking  up  the 
various  points  of  technique  so  clearly  and  concisely  laid  down  in  its  pages." — American  Alcd.- 
Surg.  Bulletin. 

FEEDING  IN  EARLY  INFANCY.  By  Arthur  V.  Meigs,  M.  D. 
Bound  in  limp  cloth,  flush  edges.     Price,  25  cents  net. 

Synopsis  :  Analyses  of  Milk — Importance  of  the  Subject  of  Feeding  in  Early 
Infancy — Proportion  of  Casein  and  Sugar  in  Human  Milk — Time  to  Begin  Arti- 
ficial Feeding  of  Infants — Amount  of  Food  to  be  Administered  at  Each  Feed- 
ing— Intervals  between  Feedings — Increase  in  Amount  of  Food  at  Different 
Periods  of  Infant  Development — Unsuitableness  of  Condensed  Milk  as  a  Sub- 
stitute for  Mother's  Milk — Objections  to  Sterilization  or  "  Pasteurization  "  of 
Milk — Advances  made  in  the  Method  of  Artificial  Feeding  of  Infants. 


CATALOGUE    OF  MEDICAL    WORKS.  \y 

ESSENTIALS  OF  ANATOMY  AND  MANUAL  OF  PRACTI- 
CAL DISSECTION,  containing  "  Hints  on  Dissection  '  By  CHARLES 
B.  Nancrede,  M.  D.,  Professor  of  Surgery  and  Clinical  Surgery  in  the 
University  of  Michigan,  Ann  Arbor;  Corresponding  Member  of  the  Royal 
Academy  of  Medicine,  Rome,  Italy ;  late  Surgeon  Jefferson  Medical  Col- 
lege, etc.  Fourth  and  revised  edition.  Post  8vo,  over  500  pages,  with 
handsome  full-page  lithographic  plates  in  colors,  and  over  200  illustrations. 
Price  :   Extra  Cloth  or  Oilcloth  for  the  dissection-room,  $2.(x>  net. 

Neither  pains  nor  expense  has  been  spared  to  make  this  work  the  most  ex- 
haustive yet  concise  Student's  Manual  of  Anatomy  and  Dissection  ever  pub- 
lished, either  in  America  or  in  Europe. 

The  colored  plates  are  designed  to  aid  the  student  in  dissecting  the  muscles, 
arteries,  veins,  and  nerves.  The  wood-cuts  have  all  been  specially  drawn  and 
engraved,  and  an  Appendix  added  containing  60  illustrations  representing  the 
structure  of  the  entire  human  skeleton,  the  whole  being  based  on  the  eleventh 
edition  of  Gray's  Anatomy. 


"  The  plates  are  of  more  than  ordinary  excellence,  and  are  of  especial  value  to  students  in 
their  work  in  the  dissecting-room." — Journal  of  American  Medical  Association. 

"Should  be  in  the  hands  of  every  medical  student." — Cleveland  Medical  Gazette. 

"A  concise  and  judicious  work." — Buffalo  Medical  and  Surgical  Journal. 


A  MANUAL  OF  PRACTICE  OF  MEDICINE.  By  A.  A.  Stevens, 
A.  M.,  M.  D.,  Instructor  of  Physical  Diagnosis  in  the  University  of  Penn- 
sylvania, and  Demonstrator  of  Pathology  in  the  Woman's  Medical  College 
of  Philadelphia.  Specially  intended  for  students  preparing  for  graduation 
and  hospital  examinations,  and  includes  the  following  sections :  General 
Diseases,  Diseases  of  the  Digestive  Organs,  Diseases  of  the  Respiratory 
System,  Diseases  of  the  Circulatory  System,  Diseases  of  the  Nervou~ 
tern,  Diseases  of  the  Blood,  Diseases  of  the  Kidneys,  and  Diseases  of  the 
Skin.  Each  section  is  prefaced  by  a  chapter  on  General  Symptomatology. 
Post  8vo,  512  pages.  Numerous  illustrations  and  selected  formula1. 
Price,  $2.50. 

FOURTH  EDITION,  REVISED  AND  ENLARGED. 

Contributions  to  the  science  of  medicine  have  poured  in  so  rapidly  during  the 
last  quarter  of  a  century  that  it  is  well-nigh  impossible  for  the  student,  with  the 
limited  time  at  his  disposal,  to  master  elaborate  treatises  or  to  cull  from  them 
that  knowledge  which  is  absolutely  essential.  From  an  extended  experience  in 
teaching,  the  author  has  been  enabled,  by  classification,  to  Ljroup  allied  symp- 
toms, and  by  the  judicious  elimination  of  theories  and  redundant  explanations 
to  bring  within  a  comparatively  small  compass  a  complete  outline  of  the  prac- 
tice of  medicine. 


W.    B.   SAUNDERS 


MANUAL    OF    MATERIA    MEDICA    AND    THERAPEUTICS. 

By  A.  A.  Stevens,  A.  M.,  M.  D.,  Instructor  of  Physical  Diagnosis  in  the 
University  of  Pennsylvania,  and  Demonstrator  of  Pathology  in  the  Woman's 
Medical  College  of  Philadelphia.     445  pages.     Price,  Cloth,  #2.25. 

SECOND   EDITION,    REVISED. 

This  wholly  new  volume,  which  is  based  on  the  last  edition  of  the  Pharma- 
copeia, comprehends  the  following  sections  :  Physiological  Action  of  Drugs ; 
Drugs;  Remedial  Measures  other  than  Drugs;  Applied  Therapeutics;  Incom- 
patibility in  Prescriptions;  Table  of  Doses;  Index  of  Drugs;  and  Index  of 
Diseases ;  the  treatment  being  elucidated  by  more  than  two  hundred  formulae. 

"  The  author  is  to  be  congratulated  upon  having  presented  the  medical  student  with  as 
accurate  a  manual  of  therapeutics  as  it  is  possible  to  prepare." — Therapeutic  Gazette. 

"  Far  superior  to  most  of  its  class  ;  in  fact,  it  is  very  good.  Moreover,  the  book  is  reliable 
and  accurate." — New  York  Medical  Journal. 

"  The  author  has  faithfully  presented  modern  therapeutics  in  a  comprehensive  work,  .  .  . 
and  it  will  be  found  a  reliable  guide."—  University  Medical  Magazine. 


NOTES  ON  THE  NEWER  REMEDIES:  their  Therapeutic  Ap- 
plications and  Modes  of  Administration.  By  David  Cerna,  M.  D., 
Ph.  D.,  Demonstrator  of  and  Lecturer  on  Experimental  Therapeutics  in 
the   University  of  Pennsylvania.     Post-octavo,   253  pages.     Price,  #1.25. 

SECOND  EDITION,  RE-WRITTEN  AND  GREATLY   ENLARGED. 

The  work  takes  up  in  alphabetical  order  all  the  newer  remedies,  giving  their 
physical  properties,  solubility,  therapeutic  applications,  administration,  and 
chemical  formula. 

It  thus  forms  a  very  valuable  addition  to  the  various  works  on  therapeutics 
now  in  existence. 

Chemists  are  so  multiplying  compounds,  that,  if  each  compound  is  to  be  thor- 
oughly studied,  investigations  must  be  carried  far  enough  to  determine  the  prac- 
tical importance  of  the  new  agents. 

"  Especially  valuable  because  of  its  completeness,  its  accuracy,  its  systematic  consider- 
ation of  the  properties  and  therapy  of  many  remedies  of  which  doctors  generally  know  but 
little,  expressed  in  a  brief  yet  terse  manner." — Chicago  Clinical  Review. 


TEMPERATURE   CHART.     Prepared  by   D.  T.  Laine,  M.  D.      Size 
8x  13%.  inches.     Price,  per  pad  of  25  charts,  50  cents. 

A  conveniently  arranged  chart  for  recording  Temperature,  with  columns  for 
daily  amounts  of  Urinary  and  Fecal  Excretions,  Food,  Remarks,  etc.  On  the 
back  of  each  chart  is  given  in  full  the  method  of  Brand  in  the  treatment  of 
Typhoid  Fever. 


CATALOGUE   OF  MEDICAL    WORKS.  1 9 


SAUNDERS'  POCKET  MEDICAL  LEXICON;  or,  Dictionary  of 
Terms  and  Words  used  in  Medicine  and  Surgery.  By  foHN  M. 
Keating,  M.  D.,  editor  of"<  ia  ol   Disi  ol  Children,"  etc. ; 

author  of  the  "  New   Prououncing  Dictionary  of  Medicine;"  and  II. 
Hamilton,  author  of  "  A  New  Translation  of  Virgil's  .Encid  into  Eng- 
lish Verse;"  co-author  of  a  "  New  Pronouncing  Dictionary  of  Medicine." 
A  new  and  revised  edition.     321110,  282  pages.     Price, :   Cloth,  75  cents; 
Leather   Tucks,  $1.00. 

This  new  and  comprehensive  work  of  reference  is  the  out.  ome  of  a  demand 
for  a  more  modern  handbook  of  it,  class  than  tho  market, 

which,  dating  as  they  do  from  1S55  to  1884,  are  ol  but  trifling  use  to  the  student 
by  their  not  containing  the  hundreds  of  new  words  now  used  in  current  litera- 
ture, especially  those  relating  to  Electricity  and  Bacteriology. 

*'  Remarkably  accurate  in  terminology,  accentuation,  and  definition."— Journal  of  'Amer- 
ican Medical  Association. 

"  Brief,  yet  complete  ....  it  contains  the  very  latest  nomenclature  in  even  the  newest 
departments  of  medicine." — New  York  Medical  Record. 


SAUNDERS'  POCKET  MEDICAL  FORMULARY.  By  William 
M.  POWEI  1.  M.  D.,  Attending  Physician  to  the  Mercer  House  for  Invalid 
Women  at  Atlantic  City.  Containing  1750  Formula;,  selected  from  several 
hundred  of  the  best  known  authorities.  Forming  a  handsome  and  con- 
venient pocket  companion  of  nearly  300  printed  page-,  with  blank  leaves 
for  Additions;  with  an  Appendix  containing  Posological  Table,  Formula; 
and  Doses  for  Hypodermatic  Medication,  Poisons  and  their  Antidotes, 
Diameters  of  the  Female  Pelvis  and  Fnetal  Head,  Obstetrical  Table.  Diet 
List  for  Various  Disease^.  Material,  and  Drugs  used  in  Antiseptic  Surgery, 
Treatment  of  Asphyxia  from  Drowning,  Surgical  Remembrancer,  Tables 
of  Incompatibles,  Eruptive  Fevers,  Weights  and  Measures,  etc.  Third 
edition,  revised  and  greatly  enlarged.  Handsomely  bound  in  morocco, 
with  ,ide  index,  wallet,  and  flap.      Price,  51.75  net. 

A  concise,  clear,  and  correct  record  of  the  many  hundreds  of  famous  formulae 
which  are  found  scattered  through  the  works  of  the  most  eminent  physicians 
and  surgeons  of  the  world.  The  work  is  helpful  to  the  student  and  practitioner 
alike,  as  through  it  they  become  acquainted  with  numerous  formulae  which  are 
not  found  in  text-books,  but  have  been  collected  from  among  the  ri 
Hon  of  the  profession,  college  professors,  and  hospital  physicians  ana 

"This  little  hook,  that  can  be  conveniently  carried  in  the  pocket,  contains  an  immense 
amount  of  material.  It  is  very  useful,  and  as  the  name  of  the  author  of  each  prescription  is 
given  is  unusually  reliable." — New  York  Medical  Record. 

"  Designed  to  be  of  immense  help  to  the  general  practitioner  in  the  exercise  of  his  daily 
calling." — Boston  Medical  and  Surgical  Journal. 


20  W.   B.    SAUNDERS' 


DISEASES  OF  WOMEN.  By  Henry  J.  Garrigues,  A.M.,  M.  D., 
Professor  of  Gynecology  and  Obstetrics  in  the  New  York  School  of  Clinical 
Medicine;  Gynecologist  to  St.  Mark's  Hospital  and  to  the  German  Dis- 
pensary, New  York  City.  In  one  handsome  octavo  volume  of  728  pages, 
illustrated  by  335  engravings  and  colored  plates.  Prices:  Cloth,  $4.00  net; 
Sheep  or  Half  Morocco,  $5.00  net. 

A  PRACTICAL  work  on  gynecology  for  the  use  of  students  and  practitioners, 
written  in  a  terse  and  concise  manner.  The  importance  of  a  thorough  know- 
ledge of  the  anatomy  of  the  female  pelvic  organs  has  been  fully  recognized  by 
the  author,  and  considerable  space  has  been  devoted  to  the  subject.  The  chap- 
ters on  Operations  and  on  Treatment  are  thoroughly  modern,  and  are  based 
upon  the  large  hospital  and  private  practice  of  the  author.  The  text  is  eluci- 
dated by  a  large  number  of  illustrations  and  colored  plates,  many  of  them  being 
original,  and  forming  a  complete  atlas  for  studying  embryology  and  the  anatomy 
of  the  female  genitalia,  besides  exemplifying,  whenever  needed,  morbid  condi- 
tions, instruments,  apparatus,  and  operations. 

Second  Edition,  Thoroughly  Revised. 

The  first  edition  of  this  work  met  with  a  most  appreciative  reception  by  the 
medical  press  and  profession  both  in  this  country  and  abroad,  and  was  adopted 
as  a  text-book  or  recommended  as  a  book  of  reference  by  nearly  one  hundred 
colleges  in  the  United  States  and  Canada.  The  author  has  availed  himself  of 
the  opportunity  afforded  by  this  revision  to  embody  (he  latest  approved  advances 
in  the  treatment  employed  in  this  important  branch  of  Medicine.  He  has  also 
more  extensively  expressed  his  own  opinion  on  the  comparative  value  of  the 
different  methods  of  treatment  employed. 

"One  of  the  best  text-books  for  students  and  practitioners  which  has  been  published  in 
the  English  language;  it  is  condensed,  clear,  and  comprehensive.  The  profound  learning 
and  great  clinical  experience  of  the  distinguished  author  find  expression  in  this  book  in  a 
most  attractive  and  instructive  form.  Young  practitioners,  to  whom  experienced  consultants 
may  not  be  available,  will  find  in  this  book  invaluable  counsel  and  help." 

Thad.  A.  Reamy,  M.  D.,  LL.D., 

Professor  of  Clinical  Gynecology ,  Medical  College  of  Ohio  ;   Gynecologist  to  the  Good 
Samaritan  and  Cincinnati  Hospitals. 


A   SYLLABUS  OF  GYNECOLOGY,   arranged    in  conformity  with 
"An  American  Text-Book  of  Gynecology."    By  J.  W.  Long,  M.  D., 

Professor  of  Diseases  of  Women  and  Children,  Medical  College  of  Vir- 
ginia, etc.     Price,  Cloth  (interleaved),  $1.00  net. 

Based  upon  the  teaching  and  methods  laid  down  in  the  larger  work,  this  will 
not  only  be  useful  as  a  supplementary  volume,  but  to  those  who  do  not  already 
posses?  the  text-book  it  will  also  have  an  independent  value  as  an  aid  to  the 
practitioner  in  gynecological  work,  and  to  the  student  as  a  guide  in  the  lecture- 
room,  as  the  subject  is  presented  in  a  manner  at  once  systematic,  clear,  succinct, 
and  practical. 


CATALOGUE    OF  MEDICAL    WORKS.  21 

A  MANUAL    OF    PHYSIOLOGY,  with    Practical    Exercises.     For 

Students  and  Practitioners.     By  <i.  N.  STEWART,  M.  A.,  M.  D  .  I 

lately  Examiner  in   Physiology,  University  of  Aberdeen,  and  "f  the  New 

Museums,  Cambridge  University;   Professor  of  Physiology  in  i! 

Reserve  University,  Cleveland,  Ohio.     Handsome  octavi  I   800 

pages,  with  278   illustrations    in    the    text,  ami  5  colored    plati 

Cloth,  S3. 50  net. 

"  It  will  mike  its  way  by  sheer  force  of  merit,  and  amply  deserves  to  do  so.  It  is  one  oj 
the  very  best  English  text-books  on  the  subject." — London  Lancet. 

"Of  the  many  text-books  of  physiology  published,  we  do  not  know  of  one  that  so  nearly 
comes  up  to  the  ideal  as  does  Professor  Stewart's  volume." — British  Medical  Journal. 

ESSENTIALS  OF  PHYSICAL  DIAGNOSIS  OF  THE  THORAX. 
By  ARTHUR  M.  CORWIN,  A.  M.,  M.  1).,  Demonstrator  of  Physical  Diaj 

sis  in  the  Rush  Medical  College,  Chicago;  Attending  Physician  to  the 
Central  Free  Dispensary,  Department  of  Rhinology,  Laryngology,  and 
Diseases  of  the  Chest.  200  pages.  Illustrated.  Cloth,  flexible  covers. 
Price,  Si. 25   net. 

SYLLABUS    OF    OBSTETRICAL    LECTURES    in    the    Medical 
Department,  University  of  Pennsylvania.     By  RICHARD  C.  Noi 
A.   M.,  M.   D.,  Lecturer  on  Clinical  and  Operative  Obstetrics,  Unh 

of  Pennsvlvania.  Third  edition,  thoroughly  revised  and  enlarged.  Crown 
8vo.     Price,  Cloth,  interleaved  for  notes,  $2.00  net. 

"  This  work  is  so  far  superior  to  others  on  the  same  subject  that  we  take  pleasure  in  call- 
ing attention  briefly  to  its  excellent  features.  It  covers  the  subject  thoroughly,  and  will 
prove  invaluable  both  to  the  student  and  the  practitioner.  The  author  has  introduced  a 
number  of  valuable  hints  which  would  only  occur  to  one  who  was  himself  an  experienced 
teacher  of  obstetrics.  The  subject-matter  is  clear,  forcible,  and  modern.  We  are  especially 
pleased  with  the  portion  devoted  to  the  practical  duties  of  the  accoucheur,  care  of  the  child, 
etc.  The  paragraphs  on  antisf-ptics  are  admirable;  there  is  no  doubtful  tone  in  the^  direc- 
tions given.  No  details  are  regarded  as  unimportant ;  no  minor  matters  omitted.  We  ven- 
»ay  that  even  the  old  practitioner  will  find  useful  hints  in  this  direction  which  he  can- 
not afford  to  despise." — New  York  Medical  Record. 

A  SYLLABUS  OF  LECTURES  ON  THE  PRACTICE  OF  SUR- 
GERY, arranged  in  conformity  with  "  An  American  Text-Book 
of  Surgery."  By  X.  SENN,  M.  D.,  Ph.  D.,  Professor  of  Surgery  in  Rush 
Medical  College,  Chicago,  and  in  the  Chicago  Polyclinic.     Price,  $2.00. 

This,  the  latest  work  of  its  eminent  author,  himself  one  of  the  contributors 
to  "An  American    Text  Book  of  Surgery,"  will  prove  of  exceptional  value  to 
the  advanced  student  who  has  adopted  that  work  as  his  text-book.     It  i<  not 
only  the  syllabus  of  an  unrivalled   course  of  surgical  practice,  but  it  is  .1' 
epitome  of  or  supplement  to  the  larger  work. 

"  The  author  has  evidently  spared  no  pains  in  makinc  his  Syllabus  thoroughly  comprehen- 
sive, and  has  added  new  matter  and  alluded  to  the  most  recent  authors  •«  Full 
references  are  also  given  to  all  requisite  details  of  surgical  anatomy  and  pathology." — British 
Medical  Journal,  London. 


22  W.    B,    SAUNDERS' 


AN  OPERATION  BLANK,  with  Lists  of  Instruments,  etc.  re- 
quired in  Various  Operations.  Prepared  by  W.  W.  Keen,  M.  D., 
LL.D.,  Professor  of  Principles  of  Surgery  in  the  Jefferson  Medical  Col- 
lege, Philadelphia.  Price  per  Pad,  containing  Blanks  for  fifty  operations, 
50  cents  net. 

SECOND  EDITION,  REVISED  FORM. 

A  convenient  blank,  suitable  for  all  operations,  giving  complete  instructions 
regarding  necessary  preparation  of  patient,  etc.,  with  a  full  list  of  dressings  and 
medicines  to  be  employed. 

On  the  back  of  each  blank  is  a  list  of  instruments  used— viz.  general  instru- 
ments, etc.,  required  for  all  operations ;  and  special  instruments  for  surgery  of 
the  brain  and  spine,  mouth  and  throat,  abdomen,  rectum,  male  and  female 
genito-urinary  organs,  the  bones,  etc. 

The  whole  forming  a  neat  pad,  arranged  for  hanging  on  the  wall  of  a  sur- 
geon's office  or  in  the  hospital  operating-room. 

"Will  serve  a  useful  purpose  for  the  surgeon  in  reminding  him  of  the  details  of  prepa- 
ration for  the  patient  and  the  room  as  well  as  for  the  instruments,  dressings,  and  antiseptics 
needed  " — New  Y01  k  Medical  Record 

"  Covers  about  all  that  can  be  needed  in  any  operation."— American  Lancet 

"The  plan  is  a  capital  one." — Boston  Medical  and  Surgical  yournal. 

LABORATORY  EXERCISES  IN  BOTANY.  By  Edson  S.  Bastin, 
M.  A.,  Professor  of  Materia  Medica  and  Botany  in  the  Philadelphia  Col- 
lege of  Pharmacy.  Octavo  volume  of  536  pages,  87  full-page  plates.  Price, 
Cloth,  $2.50. 

This  work  is  intended  for  the  beginner  and  the  advanced  student,  and  it  fully 
covers  the  structure  of  flowering  plants,  roots,  ordinary  stems,  rhizomes,  tubers, 
bulbs,  leaves,  flowers,  fruits,  and  seeds.  Particular  attention  is  given  to  the  gross 
and  microscopical  structure  of  plants,  and  to  those  used  in  medicine.  Illustra- 
tions have  freely  been  used  to  elucidate  the  text,  and  a  complete  index  to  facil- 
itate reference  has  been  added. 

"  There  is  no  work  like  it  in  the  pharmaceutical  or  botanical  literature  of  this  country,  and 
we  predict  for  it  a  wide  circulation." — American  yournal  of  Pharmacy. 

DIET  IN  SICKNESS  AND  IN  HEALTH.  By  Mrs.  Ernest  Hart, 
formerly  Student  of  the  Faculty  of  Medicine  of  Paris  and  of  the  London 
School  of  Medicine  for  Women ;  with  an  Introduction  by  Sir  Henry 
Thompson,  F.  R.  C.  S.,  M.  I).,  London.  220  pages ;  illustrated.  Price, 
Cloth,  $1.50. 

Useful  to  those  who  have  to  nurse,  feed,  and  prescribe  for  the  sick.  In 
each  case  the  accepted  causation  of  the  disease  and  the  reasons  for  the  special 
diet  prescribed  are  briefly  described.  Medical  men  will  find  the  dietaries  and 
recipes  practically  useful,  and  likely  to  save  them  trouble  in  directing  the  dietetic 
treatment  of  patients. 


CATALOGUE    OF  MEDICAL    WORKS.  2$ 


HOW  TO  EXAMINE  FOR  LIFE  INSURANCE.  By  Joi 
Keating,  M.D.,  Fellow  of  the  College  of  Physicians  and  Sui 
Philadelphia;  Vice-President  of  the  American  Pediatric  Society;  1  •- 
President  of  the  Association  of  Fife  Insurance  Medical  Directors.  Royal 
8vo,  211  pages,  with  two  large  half-tone  illustrations,  and  a  plate  prepared 
by  Dr.  McClellan  from  special  dissections;  also,  numerous  cuts  to  elucidate 
the  text.     Second  edition.     Price,  (huh,  .S2.00  net. 

"This  is  by  far  die  most  useful  book  which  has  yet  appeared  on  insurance  examination  a 
subject  of  growing  interest  and  importance.  Not  the  least  valuable  portion  of  the  volume  is 
Part  II.,  which  consists  of  instructions  issued  to  their  examining  physicians  by  twenty-four 
representative  companies  of  this  country.  As  the  proofs  of  these  instructions  were  corrected 
by  the  directors  of  the  companies,  they  form  the  latest  instructions  obtainable.  If  for  these 
alone,  the  book  should  be  at  the  right  hand  of  every  physician  interested  in  this  special  branch 
of  medical  science." — The  Medical  News,  Philadelphia. 

NURSING:  ITS  PRINCIPLES  AND  PRACTICE.  By  Isabel 
Adams  Hampton,  Graduate  of  the  New  York  Training  School  for 
Nurses  attached  to  Bellevue  Hospital;  Superintendent  of  Nurses  and 
Principal  of  the  Training  School  for  Nurses,  Johns  Hopkins  Hospital, 
Baltimore,  Md. ;  late  Superintendent  of  Nurses,  Illinois  Training  School 
for  Nurses,  Chicago,  111.  In  one  very  handsome  i2mo  volume  of  484 
pages,  profusely  illustrated.     Price,  Cloth,  S2.00  net. 

This  original  work  on  the  important  subject  of  nursing  is  at  once  comprehensive 
and  systematic.  It  is  written  in  a  clear,  accurate,  and  readable  style,  suitable 
alike  to  the  student  and  the  lay  reader.  Such  a  work  has  long  been  a  desidera- 
tum with  those  entrusted  with  the  management  of  hospitals  and  the  instruction  of 
nurses  in  training-schools.  It  is  also  of  especial  value  to  the  graduated  nurse 
who  tlesires  to  acquire  a  practical  working  knowledge  of  the  care  of  the  sick 
and  the  hygiene  of  the  sick-room. 

OBSTETRIC  ACCIDENTS,  EMERGENCIES,  AND  OPERA- 
TIONS.    By  L.  C'11.   Boisliniere,   M.  D.,  late  Emeritus   Professor  of 

Obstetrics  in  the  St.  Louis  Medical  College.     381  pages,  handsomely  illus- 
trated.    Price,  S2.00  net. 

"  For  the  use  of  the  practitioner  who,  when  away  from  home,  has  not  the 
opportunity  of  consulting  a  library  or  of  calling  a  friend  in  consultation.  He 
then,  being  thrown  upon  his  own  resources,  will  find  this  book  of  benefit  in 
guiding  and  assisting  him  in  emergencies." 

INFANT'S  WEIGHT  CHART.     Designed  by  J.  P.  CROZ1  r  GRIFFITH, 

M.  D.,  Clinical  Professor  of  Diseases  of  Children  in  the  University  of  Penn- 
sylvania.   25  charts  in  each  pad.     Price  per  pad,  50  cents  net. 

A  convenient  blank  for  keeping  a  record  of  the  child's  weight  during  the  first 
tw  1  years  of  life.  Printed  on  each  chart  is  a  curve  representing  the  average  weight 
of  a  healthy  infant,  so  that  any  deviation  from  the  normal  can  readil) 


24  tV.   B.   SAUNDERS' 


THE  CARE  OF  THE  BABY.  By  J.  P.  Crozer  Griffith,  M.  D., 
Clinical  Professor  of  Diseases  of  Children,  University  of  Pennsylvania; 
Physician  to  the  Children's  Hospital,  Philadelphia,  etc.  392  pages,  with 
67  illustrations  in  the  text,  and  5  plates.     i2mo.     Price,  51.50. 

A  reliable  guide  not  only  for  mothers,  but  also  for  medical  students  and 
practitioners  whose  opportunities  for  observing  children  have  been  limited. 

"  The  whole  book  is  characterized  by  rare  good  sense,  and  is  evidently  written  by  a  mas- 
ter hand.  _  It  can  be  read  with  benefit  not  only  by  mothers,  but  by  medical  students  and  by 
any  practitioners  who  have  not  had  large  opportunities  for  observing  children." — American 
yournal  of  Obstetrics. 

THE  NURSE'S  DICTIONARY  of  Medical  Terms  and  Nursing 
Treatment,  containing  Definitions  of  the  Principal  Medical  and  Nursing 
Terms,  Abbreviations,  and  Physiological  Names,  and  Descriptions  of  the 
Instruments,  Drugs,  Diseases,  Accidents,  Treatments,  Operations,  Foods, 
Appliances,  etc.  encountered  in  the  ward  or  in  the  sick-room.  Compiled 
for  the  use  of  nurses.  By  Honnor  Morten,  author  of  "  How  to  Become 
a  Nurse,"  "Sketches  of  Hospital  Life,"  etc.  i6mo,  140  pages.  Price, 
Cloth,  $  1. 00. 

This  little  volume  is  intended  for  use  merely  as  a  small  reference-book  which 
can  be  consulted  at  the  bedside  or  in  the  ward.  It  gives  sufficient  explanation 
to  the  nurse  to  enable  her  to  comprehend  a  case  until  she  has  leisure  to  look  up 
larger  and  fuller  works  on  the  subject. 

DIET  LISTS  AND  SICK-ROOM  DIETARY.  By  Jerome  B.  Thomas, 
M.  D.,  Visiting  Physician  to  the  Home  for  Friendless  Women  and  Children 
and  to  the  Newsboys'  Home ;  Assistant  Visiting  Physician  to  the  Kings 
County  Hospital ;  Assistant  Bacteriologist,  Brooklyn  Health  Department. 
Price,  Cloth,  $1.50    (Send  for  specimen  List.) 

One  hundred  and  sixty  detachable  (perforated)  diet  lists  for  Albuminuria, 
Anaemia  and  Debility,  Constipation,  Diabetes,  Diarrhoea,  Dyspepsia,  Fevers, 
Gout  or  Uric-Acid  Diathesis,  Obesity,  and  Tuberculosis.  Also  forty  detachable 
sheets  of  Sick-Room  Dietary,  containing  full  instructions  for  preparation  of 
easily-digested  foods  necessary  for  invalids.  Each  list  is  numbered  only,  the 
disease  for  which  it  is  to  be  used  in  no  case  being  mentioned,  an  index  key 
being  reserved  for  the  physician's  private  use. 

DIETS  FOR  INFANTS  AND  CHILDREN  IN  HEALTH  AND 
IN  DISEASE.  By  Louis  Starr,  M.  D.,  Editor  of  "  An  American 
Text-Book  of  the  Diseases  of  Children."  230  blanks  (pocket-book  size), 
perforated  and  neatly  bound  in  flexible  morocco.     Price,  $1.25  net. 

The  first  series  of  blanks  are  prepared  for  the  first  seven  months  of  infant 
life ;  each  blank  indicates  the  ingredients,  but  not  the  quantities,  of  the  food, 
the  latter  directions  being  left  for  the  physician.  After  the  seventh  month, 
modifications  being  less  necessary,  the  diet  lists  are  printed  in  full.  Formula 
foj  trie  preparation  of  diluents  and  foods  are  appended. 


Practical,   Exhaustive,  Authoritative. 

SAUNDERS' 

NEW  AID  SERIES  OF  MANUALS 

FOR 

Students  and  Practitioners. 


Mr.  SAUNDERS  is  pleased  to  announce  as  now  ready  his  NEW  AID 
SERIES  OF  MANUALS  for  Students  and  Practitioners.  As  pub- 
lisher of  the  Standard  Series  <u  Question  Compends, and  through  intimate 
relations  with  leading  members  of  the  medical  profession,  Mr.  Saunders  has 
been  enabled  to  study  progressively  the  essential  desiderata  in  practical  "self- 
helps  "  for  students  and  physicians. 

This  study  has  manifested  that,  while  the  published  "  Question  Compends"' 
earn  the  highest  appreciation  of  students,  whom  they  serve  in  reviewing  their 
studies  preparatory  to  examination,  there  is  special  need  of  thoroughly  reliable 
handbooks  on  the  leading  branches  of  Medicine  and  Surgery,  each  subject 
being  compactly  and  authoritatively  written,  and  exhaustive  in  detail,  without 
the  introduction  of  cases  and  foreign  subject-matter  which  so  largely  expand 
ordinary  text-books. 

The  Saunders  Aid  Series  will  not  merely  be  condensations  from 
present  literature,  but  will  be  ably  written  by  well-known  authors 
and  practitioners,  most  of  them  being  teachers  in  representative 
American  Colleges.  This  nc~v  series,  therefore,  will  form  an  admirable 
collection  of  advanced  lectures,  which  will  be  invaluable  aids  to  students  in 
reading  and  in  comprehending  the  contents  of  "  recommended  "  works. 

Each  Manual  will  further  be  distinguished  by  the  beauty  of  the 
by  the  quality  of  the  paper  and  printing  ;  by  the  copious  use  of  illustrations  ; 
by  the  attractive  binding  in  cloth;  and  by  their  extremely  low  prii 

-5 


SAUNDERS'  NEW  AID  SERIES  OF  MANUALS. 

VOLUMES  PUBLISHED. 


PHYSIOLOGY.  By  Joseph  Howard  Raymond,  A.  M  ,  M.  D.,  Professor 
of  Physiology  and  Hygiene  and  Lecturer  on  Gynecology  in  the  Long 
Island  College   Hospital,  etc.      Price,  $1.25  net. 

SURGERY,  General  and  Operative.  By  John  Chalmers  DaCosta, 
M.  D,,  Demonstrator  of  Surgery,  Jefferson  Medical  College,  Philadelphia, 
etc.     Double  number.     Price,  #$2.50  net. 

DOSE-BOOK  AND  MANUAL  OF  PRESCRIPTION- WRITING. 

By  E.  Q.  Thornton,    M.  D.,  Demonstrator   of  Therapeutics,  Jefferson 
Medical  College,  Philadelphia.     Price,  $1.25  net. 

MEDICAL  JURISPRUDENCE.  By  Henry  C.  Chapman,  M.  D.,  Pro- 
fessor of  Institutes  of  Medicine  and  Medical  Jurisprudence  in  the  Jeffer- 
son Medical  College  of  Philadelphia,  etc      Price,  #1.50  net. 

SURGICAL  ASEPSIS.  By  Carl  Beck,  M.  D.,  Surgeon  to  St.  Mark's 
Hospital  and  to  the  German  Poliklinik  ;  Instructor  in  Surgery,  New  York 
Post-Graduate  Medical  School,  etc.     Price,  $1.25  net. 

MANUAL  OF  ANATOMY.  By  Irving  S.  Haynes,  M.  D.,  Adjunct 
Professor  of  Anatomy  and  Demonstrator  of  Anatomy,  Medical  Department 
of  the  New  York  University,  etc.      (Double  number.)     Price,  $2.50  net. 

SYPHILIS  AND  THE  VENEREAL  DISEASES.  By  James 
Nevins  Hyde,  M.  D.,  Professor  of  Skin  and  Venereal  Diseases,  and 
Frank  H.  Montgomery,  M.  D.,  Lecturer  on  Dermatology  and  Genito- 
urinary Diseases,  in  Rush  Medical  College,  Chicago.  (Double  number.) 
Price,  $2.50  net. 

PRACTICE  OF  MEDICINE.  By  George  Roe  Lockwood,  M.  D., 
Professor  of  Practice  in  the  Woman's  Medical  College  of  the  New 
York  Infirmary,  etc.     (Double  number.)     Price,  $2.50  net. 

OBSTETRICS.  By  W.  A.  Newman  Dorland,  M.  D.,  Asst.  Demonstrator 
of  Obstetrics,  University  of  Pennsylvania ;  Chief  of  Gynecological  Dispen- 
sary, Pennsylvania  Hospital.     (Double  number.)     Price,  #2.50  net. 

DISEASES  OF  WOMEN.  By  J.  Bland  Sutton,  F.  R.  C.  S.,  Assistant 
.Surgeon  to  the  Middlesex  Hospital,  and  Surgeon  to  the  Chelsea  Hospital 
for  Women,  London;  and  Arthur  E.  Giles,  M.  D.,  B.  Sc.  Lond., 
F.  R.  C.  S.  Edin.,  Assistant  Surgeon  to  the  Chelsea  Hospital  for  Women, 
London.  436  pages,  handsomely  illustrated.  (Double  number.)  Price, 
$2.50  net. 

VOLUMES  IN  PREPARATION. 
NERVOUS  DISEASES.     By  Charles  W.  Burr,  M.  D.,  Clinical  Pro- 
fessor of  Nervous  Diseases,  Medico-Chirurgical   College,  Philadelphia,  etc. 

NOSE  AND  THROAT.  By  D.  Braden  Kyll,  M.  D.,  Chief  Laryngolo- 
gist  to  St.  Agnes'  Hospital,  Philadelphia;  Instructor  in  Clinical  Microscopy 
and  Assistant  Demonstrator  of  Pathology  in  Jefferson  Medical  College. 

***  There  will  be  published   in   the   same  series,  at   short   intervals,   carefully 
prepared  works  on  various  subjects,  by  prominent  specialists. 


SAUNDERS'  QUESTION  COMPENDS. 

Arranged  in  Question  and  Answer  Form. 

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They  are  the  advance  guard  of  "  Student's  Helps  " — that  do  HELP;  they  are 
the  leaders  in  their  special  line,  well  and  authoritatively  written  by  able  men, 
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preparing  for  his  examinations.  The  judgment  exercised  in  the  selection  of 
authors  is  fully  demonstrated  by  their  professional  elevation.  Chosen  from  the 
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Each  book  is  of  convenient  size  (5x7  inches),  containing  on  an  average  250 
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fine  paper. 

The  entire  series,  numbering  twenty- four  subjects,  has  been  kept  thoroughly 
revised  and  enlarged  when  necessary,  many  of  them  being  in  their  fourth  and 
fifth  editions. 

TO   SUM    UP. 

Although  there  are  numerous  other  Quizzes,  Manuals,  Aids.  etc.  in  the  mar- 
ket, none  of  them  approach  the  "Blue  Series  of  Question  Compends;"  and 
the  claim  is  made  for  the  following  points  of  excellence : 

1.  Professional  distinction  and  reputation  of  authors. 

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Any  of  these  Compends  will  be  mailed  on  receipt  of  price   see  over 
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SAUNDERS'  QUESTlON-COMPEiNl)  SERIES. 

Price,  Cloth,  $1.00  per  copy,  except  when  otherwise  noted. 


1.  ESSENTIALS  OF  PHYSIOLOGY.    4th  edition.     Illustrated.      Re- 

vised and  enlarged  by  H.  A.  Hare,  M.  D      (Price,  $1.00  net.) 

2.  ESSENTIALS  OF  SURGERY.     6th  edition,  with  an  Appendix  on 

Antiseptic  Surgery.     90  illustrations.     By  Edward  Martin,  M.  D. 

3.  ESSENTIALS  OF  ANATOMY.    5th  edition,  with  an  Appendix.     180 

illustrations.     By  Charles  B.  Nancrede,  M.  D. 

4.  ESSENTIALS  OF  MEDICAL  CHEMISTRY,  ORGANIC  AND 

INORGANIC.  4th  edition,  revised,  with  an  Appendix.  By  Law- 
rence Wolff,  M.  D. 

5.  ESSENTIALS    OF    OBSTETRICS.     4th  edition,    revised    and    en- 

larged.    75  illustrations.     By  W.  Easterly  Ashton,  M.  D. 

6.  ESSENTIALS  OF  PATHOLOGY  AND  MORBID  ANATOMY. 

7th  thousand.     46  illustrations.     By  C.  E.  Armand  Semple,  M.  D. 

7.  ESSENTIALS    OF    MATERIA   MEDICA,    THERAPEUTICS, 

AND  PRESCRIPTION-WRITING.  4th  edition.  By  Henry 
Morris,  M.  D. 

8.  9.   ESSENTIALS  OF  PRACTICE   OF  MEDICINE.     By  Henry 

Morris,  M.  D.  An  Appendix  on  Urine  Examination.  Illustrated. 
By  Lawrence  Wolff,  M.  D.  3d  edition,  enlarged  by  some  300  Es- 
sential Formulae,  selected  from  eminent  authorities,  by  Wm.  M.  Powell, 
M.  D.     (Double  number,  price  $2.00.) 

10.  ESSENTIALS  OF  GYNECOLOGY.     4th  edition,  revised.     With 

62  illustrations.     By  Edwin  B.  Cragin,  M.  D. 

11.  ESSENTIALS  OF  DISEASES   OF  THE  SKIN.     3d  edition,  re- 

vised and  enlarged.  71  letter-press  cuts  and  15  half-tone  illustrations. 
By  Henry  W.  Stelwagon,  M.  D.     (Price,  $1.00  net.) 

12.  ESSENTIALS  OF  MINOR  SURGERY,  BANDAGING,  AND 

VENEREAL  DISEASES.  2d  edition,  revised  and  enlarged.  78 
illustrations.     By  Edward  Martin,  M.  D. 

13.  ESSENTIALS  OF  LEGAL  MEDICINE,  TOXICOLOGY,  AND 

HYGIENE.     130  illustrations.     By  C.  E.  Armand  Semple,  M.  D. 

14.  ESSENTIALS  OF  DISEASES  OF  THE  EYE,  NOSE,  AND 

THROAT.  124  illustrations.  2d  edition,  revised.  By  Edward 
Jackson,  M.  D.,  and  E.  Baldwin  Gleason,  M.  D. 

15.  ESSENTIALS  OF  DISEASES  OF  CHILDREN.     Second  edi- 

tion.    By  William  H.  Powell,  M.  D. 

16.  ESSENTIALS    OF    EXAMINATION    OF    URINE.      Colored 

"  Vogel  Scale,"  and  numerous  illustrations.  By  Lawrence  Wolff, 
M.  D.     (Price,  75  cents.) 

17.  ESSENTIALS  OF  DIAGNOSIS.     By  S.  Solis-Cohen,  M.  D.,  and 

A.  A.  Eshner,  M.  D.     55  illustrations,  some  in  colors.    (Price,  $1.50  net.) 

18.  ESSENTIALS   OF   PRACTICE   OF   PHARMACY.     By   L.   E. 

Sayre.     2d  edition,  revised. 

20.  ESSENTIALS    OF    BACTERIOLOGY.     3d  edition.     82    illustra- 

tions.    By  M.  V.  Ball,  M.  D. 

21.  ESSENTIALS  OF  NERVOUS  DISEASES  AND  INSANITY. 

48  illustrations.     3d  edition,  revised.     By  John  C.  Shaw,  M.  D. 

22.  ESSENTIALS  OF  MEDICAL  PHYSICS.      155  illustrations.     2d 

edition,  revised.     By  Fred  J.  Brockway,  M.  D.     (Price,  $1.00  net.) 

23.  ESSENTIALS  OF  MEDICAL  ELECTRICITY.     65  illustrations. 

By  David  D.  Stewart,  M.  D.,  and  Edward  S.  Lawrance,  M.  D. 

24.  ESSENTIALS  OF  DISEASES  OF  THE  EAR.    By  E.  B.  Glea- 

son, M.D.     114  illustrations.     Second  edition,  revised  and  enlarged. 


CATALOGUE    OF  MEDICAL    WORKS.  29 


JUST    PUBLISHED. 


A  TEXT-BOOK  OF  MATERIA  MEDICA,  THERAPEUTICS, 
AND  PHARMACOLOGY.  Iiy  George  F.  Butler,  Ph.  G.,  M  I)  . 
Professor  of  Materia  Medica  and  of  Clinical  Medicine  in  the  College  of 
Physicians  and  Surgeons,  Chicago;  Professor  of  Materia  Medica  and  Thera- 
peutics, Northwestern  University,  Woman's  Medical  School,  etc.  8vo,  858 
pages.  Illustrated.  Prices:  Cloth,  $4.00  net;  Sheep  or  Half-Morocco, 
$5.00  net. 

A  clear,  concise,  and  practical  text-book,  adapted  for  permanent  reference  no 
less  than  for  the  requirements  of  the  class-room.  The  arrangement  is  believed 
to  be  at  once  the  most  philosophical  and  rational,  as  well  as  that  best  calculated 
to  engage  the  interest  of  those  to  whom  the  academic  study  of  the  subject  is 
wont  to  offer  no  little  perplexity.  Special  attention  has  been  given  to  the 
Pharmaceutical  section,  which   is    exceptionally  lucid  and  complete. 

LECTURES  ON  RENAL  AND  URINARY  DISEASES.  By 
Robert  Saundby,  M.  D.  Edin.,  Fellow  of  the  Royal  College  of  Physi- 
cians, London,  and  of  the  Royal  Medico-Chirurgical  Society,  Physician  t<> 
the  General  Hospital;  Consulting  Physician  to  the  Eye  Hospital  and  t<> 
the  Hospital  for  Diseases  of  Women  ;  Professor  of  Medicine  in  Mason 
College,  Birmingham,  etc.  8vo,  434  pages,  with  numerous  illustrations 
and  4  colored   plates.      Price,  Cloth,  $2.50  net. 

In  these  Lectures,  which  are  a  re-issue  in  one  volume  of  the  author's  well- 
known  works  on  Bright's  Disease  and  Diabetes,  there  is  given,  within  a  modest 
compass,  a  review  of  the  piesent  state  of  knowledge  of  these  important  affect  inns, 
with  such  additions  and  suggestions  as  have  resulted  from  the  author's  thirteen 
years'  clinical  and  pathological  study  of  the  subjects.  The  lectures  have  been 
carefully  revised  and  much  new  matter  added  to  them.  There  has  also  been 
added  a  section  dealing  witli  "  Miscellaneous  Affections  of  the  Kidney,"  making 
the  book  more  complete  as  a  work  of  reference. 

ELEMENTARY  BANDAGING  AND  SURGICAL  DRESSING, 
with  I  Erections  concerning  the  Immediate  Treatment  of  <  'a>c>  ol  Emergency. 
For  the  use  of  Dressers  and  Nurses.  By  WAJ  11  k  I'vi.  F.  K.  < '.  S.,  late 
Surgeon  to  St.  Mary's  Hospital,  London.  Small  !2mo,  with  over  80  illus- 
trations.    Cloth,  flexible  covers.     Price,  75  cents  net. 

This  little  book  is  chiefly  a  condensation  of  those  portions  of  Pye's  "  Surgical 
Handicraft"  which  deal  with  bandaging,  splinting,  etc.,  and  of  those  which  treat 
of  the  management  in  the  first  instance  of  cases  of  emergency.  Withm  it--  own 
limits,  however,  the  book  is  complete,  and  it  is  hoped  that  it  will  prove  extremely 

useful  to  students  when  they  begin   their  work  in  the  wards  and  casualty  rooms, 
and  useful  also  to  surgical  nurses  and  dressers. 

"  The  directions  are  clear  and  the  illustrations  are  good." — London  I  I 
"  The  author  writes  well,  the  diagrams  are  clear,  and  the  book  itself  is  small  and  |>.>nat>le, 
although  the  paper  and  type  are  good." — British  Medical  Journal. 


JUST  ISSUED.  SOLD  BY  SUBSCRIPTION. 

ANOMALIES 

AND 

CURIOSITIES   OF    MEDICINE. 

BY 

GEORGE  M.  GOULD,  M.  D.,  and  WALTER  L.  PYLE,  M.  D. 

Several  years  of  exhaustive  research  ha\e  been  spent  by  the  authors  in  the 
great  medical  libraries  of  the  United  States  and  Europe  in  collecting  the  material 

for  this  work,    fledical  literature  of  all  ages  and  all  languages  has 

been  carefully  searched,  as  a  glance  at  the  Bibliographic  Index  will  show.     The 

facts,  which  will  be  of  extreme  value  to  the  author  and  lecturer,  have 

been  arranged  and  annotated,  and  full  reference  footnotes  given,  indicating 
whence  they  have  been  obtained. 

In  view  of  the  persistent  and  dominant  interest  in  the  anomalous  and  curious, 
a  thorough  and  systematic  collection  of  this  kind  (the  first  of  which  the 
authors  have  knowledge)  must  have  its  own  peculiar  sphere  of  usefulness. 

As  a  complete  and  authoritative  Book  of  Reference  it  will  be  of  value 
not  only  to  members  of  the  medical  profession,  but  to  all  persons  interested  in 
general  scientific,  sociologic,  and  medico-legal  topics;  in  fact,  the  general  inter- 
est of  the  subject  and  the  dearth  of  any  complete  work  upon  it  make  this 
volume  one  of  the  most  important  literary  innovations  of  the  day. 

An  especially  valuable  feature  of  the  book  consists  of  the  Indexing. 
Besides  a  complete  and  comprehensive  General  Index,  containing  numerous 
cross-references  to  the  subjects  discussed,  and  the  names  of  the  authors  of  the 
more  important  reports,  there  is  a  convenient  Bibliographic  Index  and  a 
Table  of  Contents. 

The  plan  has  been  adopted  of  printing  the  topical  headings  in  bold= 
face  type,  the  reader  being  thereby  enabled  to  tell  at  a  glance  the  subject- 
matter  of  any  particular  pnragrnph  or  page. 

Illustrations  have  been  freely  employed  throughout  the  work,  there  being 
165  relief  cuts  and  130  half-tones  in  the  text,  and  12  colored  and  half-tone  full- 
page  plates — a  total  of  over  320  separate  figures. 

The  careful  rendering  of  the  text  and  references,  the  wealth  of  illustrations, 
the  mechanical  skill  represented  in  the  typography,  the  printing,  and  the  bind- 
ing, combine  to  make  this  book  one  of  the  most  attractive  medical  publications 
ever  issued. 

Handsome  Imperial  Octavo  Volume  of  968   Pages. 
PRICES:  Cloth,  $6.00  net;    Half   Morocco,  $7.00  net. 
3° 


JUST   ISSUED, 


ANDERS'  PRACTICE  OF  MEDICINE. 

A  Text-Book  of  the  Practice  of  Medicine.     Bj   [auks  M  D     PhD 

LLD.,  Professor  of  the  Practice  ol  Medicine  and   fClinical  hirur- 

gical  College,  Philadelphia.     (  j 

MACDONALDS  SURGICAL  DIAGNOSIS  AND  TREATMENT. 

Surgical  Diagnosis  and  Treatment.     By  J.  W    Macdonai  d,  M    D..( 

Medicine  of  the  University  i.f"   Edinburgh  :    Professoi      '  y  and 

of  Clinical  Surgery,  Minneapolis  College  of  Physicians  and  Surgeons.   Cloth,  $=,.  a 
Sheep  or  Half  Morocco,  $6.00  net. 

MOORE'S  ORTHOPEDIC  SURGERY. 

Orthopedic  Surgery.     By  Iambs  E.  M is,  M   I)  ,  Professor  of  Orthopedics  and 

Adjunct  Professor  ot  Clinical  Surgery,  University  of  Minnes 

and  Surgery      Octavo,  356  pages,  handsomely  illustrated.     Clot)     | 

PENROSE'S   DISEASES  OF  W^MEN. 

A  Text-Book  of  Diseases  of  Women.     By  Charles  B.  1  I.D      Ph  D 

Professor  of  Gynecology,  University  ol  Pennsylvania:  Surgeon  to  Gynecean  Hospital, 
Philadelphia.     Octavo  volume  of  529  pages,  handsomely  illustrated.     Price,  £3.50  net. 

MALLORY  AND  WRIGHT'S   PATHOLOGICAL  TECHNIQUE. 

Pathological  Technique.     By  Frank  B    Mallory,  A   M  .  M.  I>  .  Asst.   Pi 

of  Pathology,  Harvard  University  Medical  School;  and  JAMES  H.  W111.nr,  A  M., 
M.  D  ,  Instructor  in  Pathology.  Harvard  University  Medical  School.  Octavo  volume 
of  306  pages,  handsomely  illustrated.     Price,  $2.50  net. 

SENN'S  GENITOURINARY   TUBERCULOSIS. 

Tuberculosis  of  the  Genito-Urinary  Organs,  Male  and  Female.     By  Ni 

Sinn,  M.  D.,  Ph.1>  .  LL  D.,  Professor  of  the  Practice  of  Surgery  and  of  Clinical  Sur- 
gery, Rush  Medical  College,  Chicago.  Handsome  octavo  volume  of  320  pages.  Illus- 
trated.    Price,  $3.00  net. 

SUTTON   AND  GILES'    DISEASES  OF   WOMEN. 

Diseases  of  Women.     By  I    Bland  Sutton,  F.  R.t  >-i;eon  to  Middlesex 

Hospital,  London;  and  ARTHUR  E.  GlLBS,  M.  D  ,  U.S.  ,  1-  R.  C  5.,  Asst.  Surgeon  ic 
Chelsea  Hospital,  London.     436  pages,  handsomely  illustrated.     Price,  $2.50  net. 


IN    PREPARATION. 

VAN   VALZAH   AND  NISBET'S  DISEASES  OF  THE  STOMACH. 

Diseases  of  the  Stomach.      By    William    W.  van  Valzah,  M    I'.,   1'r <fcssor  of 
General  Medicine  and   Diseases  of  the  Digestive  System  and    the  Blood.  Nev 
Polyclinic;    and  J.  Douglas  Nisbet,    M.J>..   Adjunct  Prof.  ral   Medicine 

and  Diseases  of  the  Digestive  .System  and  the  Blood,  V  n  \    rk  Polyclinic. 

AN   AMERICAN  TEXT-BOOK   OF  GENITO-URINARY   AND   SKIN   DISEASES. 
Edited  by  L.  Bolton  Has.,-.  M    l>.,  Late  Professor  of  Genito-Urinary  and  Venerea] 

Diseases.  New  York   Post-Graduate  Medical  School  and  Hospital:  and   William   A. 
Hardaway,  M.  D.,  Professor    f  Diseases  of  the  >kin,  Missouri  Med 

AN   AMERICAN  TEXT-BOOK  OF   DISEASES  OF  THE   EYE,  EAR,  NOSE,    AND 
THROAT. 

Edited  by  G.  E.  dr  Schweinitz,  M.  D  .  Professor  of  Ophthalmology  in  the  Jefl 
Medical  College;  and   B.  ALEXANDER   Randall,   M.  D.,  Professi  1  f  the 

Ear  in  the  University  of  Pennsylvania  and  in  the  Philai  mic. 

CHURCH   AND   PETERSON'S   NERVOUS   AND   MENTAL  DISEASES. 

Nervous  and  Mental  Diseases.     By  Archibald  Church,  Ml'  I  Men- 

tal   Diseases  and    Medical    lurisprudence.  Northwestern    University    M 
Chicago;    and   Frederick  "Plth;s.  in,   M    !>.,  Clinical    Professor  ..t  Menl 
Woman's  Medical   College,  New  V..rk  ;   Chief  of  Clini    .  ■  "  partment,  College 

of  Physicians  and  Surgeons,  New  York. 

HIRST'S  OBSTETRICS. 

A  Text-Book  of  Obstetrics.    By  Barton  Cooke  Hirst,  M.  1>  ,  i 

rics.  University  of  Pennsylvania. 

HEISLER'S  EMBRYOLOGY. 

A  Text- Book  of  Embryology.     By  John  C.  Hbislbr,  M    I'     Pn  sector  to  the  Pro- 
fessor of  Anatomy,  Medical  Department,  University  ol   Penns) 


XO IV  READY,   VOLUMES  FOR    1800,189  7,189$. 


S^TJISTID  ZEISS' 

AMERICAN  YEAR-BOOK  OF  MEDICINE  and  SURGERY, 

Edited   by  GEORGE  M.  GOULD,  A.  M.,  M.  D. 

Assisted  by  Eminent  American  Specialists  and  Teachers. 


Notwithstanding  the  rapid  multiplication  of  medical  and  surgical  works, 
still  these  publications  fail  to  meet  fully  the  requirements  of  the  general  physician, 


z 


inasmuch  as  he  feels  the  need  of  something  more  than  mere  text -books  of  well-    S» 


g  known  principles  of  medical  science.     Mr.  Saunders  has  long  been  impressed  ^ 

^  with  this  fact,  which  is  confirmed  by  the  unanimity  of  expression  from  the  pro-  " 

t  fession  at  large,  as  indicated  by  advices  from  his  large  corps  of  canvassers.  <5 

fc  This  deficiency  would  best  be  met  by  current  journalistic  literature,  but  most  |£ 

"£  practitioners  have  scant  access  to  this  almost  unlimited  source  of  information,  «, 

5;  and  the  busy  practiser  has  but  little  time  to  search  out  in  periodicals  the  many  5 

*  interesting  cases  whose   study  would  doubtless  be  of  inestimable  value  in  his  £ 

5  practice.     Therefore,  a  work  which  places  before  the  physician  in  convenient  fcu 

^     form  an  epitomization  of  this  literature  by  persons  competent  to  pronounce  itpon       5 
•*  «; 

5  The  Value  of  a  Discovery  or  of  a  Method  of  Treatment  «i. 

>  ......      5 

«  cannot  but  command  his  highest  appreciation.     It  is  this  critical  and  judicial  5 

.2  function  that  will  be  assumed  by  the  Editorial  staff  of  the  "  American  Year- 

"g  Book  of  Medicine  and  Surgery."  <^ 

*  It  is  the  special  purpose  of  the  Editor,  whose  experience  peculiarly  qualifies  5* 
5*  him  for  the  preparation  of  this  work,  not  only  to  review  the  contributions  to  jjg 

American  journals,  but  also  the  methods  and  discoveries  reported  in  the  leading    J 

ii    medical  journals  of  Europe,  thus  enlarging  the  survey   and  making  the  work     ' 

©     characteristically  international.     These  reviews  will  not  simply  be  a  series  of 

■*  .      .  .2(5 

5     undigested  abstracts  indiscriminately  run  together,  nor  will  they  be  retrospective     $ 

i     of  "  news  "  one  or  two  years  old,  but  the  treatment  presented  will  be  synthetic     X: 

•**     and  dogmatic,  and  will  include  only  what  is  new.      Moreover,  through  expert     • 

*  condensation  by  experienced  writers  these  discussions  will  be 

Comprised  in  a  Single  Volume  of  about  1200  Pages. 
The  work  will  be  replete  with  original  and  selected  illustrations  skilfully 
reproduced,  for  the  most  part  in  Mr.  Saunders'  own  studios  established  for  the 
purpose,  thus  ensuring  accuracy  in  delineation,  affording  efficient  aids  to  a  right 
comprehension  of  the  text,  and  adding  to  the  attractiveness  of  the  volume. 
Prices:   Cloth,  $6. 50  net ;    Half  Morocco,  $7.50  net. 

W.  B.  SAUNDERS,  Publisher, 

925  Walnut  Street,  Philadelphia. 


SECOND   EDITION, 
REVISED   AND  GREATLY  ENLARGED 


Notes  on  the  Newer  Remedies 


THERAPEUTIC  APPLICATIONS 
AND  MODES  OF  ADMINISTRATION. 


DAVID  CERNA,  M.D.,  Ph.D., 

Demonstrator  of  Physiology  in  the  Medical  Department  of  the 
University  of  Texas  ;  formerly  Demonstrator  of  and  Lect- 
urer on  Experimental   Therapeutics    in  the 
University  of  Pennsylvania. 

Post   8vo.    250  Paiges. 

PRICE,  $1.25. 


W  The  work  takes  up  in  alphabetical  order  all  the 
Newer  Remedies,  giving  their  physical  properties 
— solubility — therapeutic  application — administra- 
tion and  chemical  formula. 

It  will,  in  this  way,  form  a  very  valuable  addition 
to  the  various  works  on  Therapeutics  now  in  ex- 
istence. 

Chemists  are  so  multiplying  compounds  that  if 
each  compound  is  to  be  thoroughly  studied,  inves- 
tigations must  be  carried  far  enough  to  determine 
the  practical  importance  of  the  new  agents. 

Brevity  and  conciseness  compel  the  omission  of 
all  biographical  references. 


MANUAL 


MATERIA  MEDICA 


THERAPEUTICS. 


BY 

A.  A.  STEVENS,  A.  M.,  M.  D., 

Instructor  of  Physical  Diagnosis  in  the  University  of 

Pennsylvania,  and  Demonstrator  of  Pathology  in  the 

Woman's  Medical  College  of  Philadelphia. 


435  Pages. 
PRICE,  CLOTH,  $2.25. 


This  manual  has  been  prepared  especially 
for  students,  with  the  hope  that  it  may  serve 
as  a  thoroughly  comprehensive  outline  of 
modern  therapeutics.  The  work,  which  is  based' 
on  the  1890  edition  of  the  U.  S.  Pharmacopoeia, 
comprehends  the  following  sections:  Physio- 
logical Action  of  Drugs ;  Drugs ;  Remedial 
Measures  other  than  Drugs ;  Applied  Thera- 
peutics; Incompatibility  in  Prescriptions; 
Table  of  Doses;  Index  of  Drugs;  and  In- 
dex of  Diseases ;  the  treatment  being  eluci- 
dated by  more  than  two  hundred  formula. 


Saunders*  New  Aid  Series  of  Manuals. 


NOW   READY. 


DOSE-BOOK 


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